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WO2018190730A1 - Procédé et/ou système de traitement et/ou de réutilisation de béton non durci - Google Patents

Procédé et/ou système de traitement et/ou de réutilisation de béton non durci Download PDF

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Publication number
WO2018190730A1
WO2018190730A1 PCT/NZ2018/050049 NZ2018050049W WO2018190730A1 WO 2018190730 A1 WO2018190730 A1 WO 2018190730A1 NZ 2018050049 W NZ2018050049 W NZ 2018050049W WO 2018190730 A1 WO2018190730 A1 WO 2018190730A1
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WO
WIPO (PCT)
Prior art keywords
uncured concrete
concrete
batch
uncured
data
Prior art date
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Ceased
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PCT/NZ2018/050049
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English (en)
Inventor
Jack Douglas BRIGHT
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Ipcorp Holdings Ltd
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Ipcorp Holdings Ltd
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Filing date
Publication date
Application filed by Ipcorp Holdings Ltd filed Critical Ipcorp Holdings Ltd
Publication of WO2018190730A1 publication Critical patent/WO2018190730A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C9/00—General arrangement or layout of plant
    • B28C9/002—Mixing systems, i.e. flow charts or diagrams; Making slurries; Involving methodical aspects; Involving pretreatment of ingredients; Involving packaging
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0096—Provisions for indicating condition of the compositions or the final products, e.g. degree of homogeneous mixing, degree of wear

Definitions

  • the invention relates generally to a method and/or system of treating residual or waste uncured concrete so that it can be reused in valuable applications such as the manufacture of precast concrete products. It is particularly directed to the reuse of wet ready-mix concrete waste, that is, surplus unset or uncured concrete.
  • Concrete is the most widely used construction material on earth. Most concrete used in construction and other industrial applications is in the form of ready-mix concrete which is produced by concrete manufacturing or batching plants and transported by mixer trucks to the job site. It is very common for contractors to order more concrete than is required for a specific job in case of unforeseen issues or changes in the job. Typically, the wet (unset) residual concrete which has not been used on the job is returned by the same mixer truck to the concrete batching plant. In New Zealand alone, about 260,000 tonnes of waste (residual) unset concrete is generated every year. Whilst as a percentage of production the waste figure is small (being approximately 2.5 - 3% of production), because concrete is such an important and widespread construction material the production volumes are very large, and consequently the waste volumes are large.
  • the residual uncured concrete is a useable product. However, it is extremely perishable with an average life of only three hours which makes it very difficult to reuse. It is cumbersome and costly to deal with the residual or waste concrete so the most common practice is to dump the left over concrete, crush it and dispose of it as industrial waste in a landfill. Due to the costs involved in this disposal method, and to the obvious environmental concerns of this practice, there have been efforts in recent years to devise solutions for the recycling and reuse of residual uncured concrete.
  • re-batching Other methods have been proposed in which unset concrete is reclaimed by treating it with a retarder overnight so that it can be reused the next day in combination with new concrete, also known as "re-batching".
  • re-batching methods are not practical or commercially feasible for several reasons. Firstly, they do not provide the concrete manufacturing plant with the ability to handle residual concrete for a truck that has returned and needs to discharge the residual concrete to receive another load of concrete in the same day, which is often required.
  • the re-batching method involves treatment of a single batch of leftover concrete from one job for use in combination with fresh concrete usually having the same composition or specification in the next job. It does not allow for the reuse of multiple batches of leftover concrete or for the reuse of the concrete in a different application.
  • the invention resides in a method of producing a single batch of uncured concrete, the single batch of uncured concrete being produced by combining or aggregating a quantity of uncured concrete from at least two separately sourced batches of uncured concrete, the method including the following steps: identifying at least one characteristic of the specification or composition of the uncured concrete from each source; identifying the time that each separately sourced batch of uncured concrete was initially produced; identifying the quantity of each separately sourced batch of uncured concrete; using this identified data to calculate a quantity of inhibitor formulation to be added to each separately sourced batch of uncured concrete; mixing each calculated quantity of inhibitor formulation with its associated batch of uncured concrete; and combining the separately sourced batches of uncured concrete to produce the said single batch of uncured concrete.
  • the amount of inhibitor formulation added to each separately sourced batch of uncured concrete is calculated to synchronize the estimated cure time of each separately sourced batch of uncured concrete.
  • the estimated cure time is determined based on the time at or after which the single batch of uncured concrete is to be used in the future.
  • the method includes sourcing quantities of uncured concrete from batches of uncured concrete that were produced at different times.
  • the method includes sourcing quantities of uncured concrete from at least two separate batches wherein the specification or composition of one batch of sourced uncured concrete is different to at least one other batch of sourced uncured concrete.
  • each separately sourced batch of uncured concrete is the residual unused concrete remaining in a concrete mixer truck after a job, and the uncured concrete is treated with the inhibitor formulation in-truck before being discharged into a receiving unit.
  • the residual uncured concrete is treated with inhibitor formulation in the receiving unit or at the location of discharge from the truck.
  • the method incorporates a computerised system adapted to calculate the amount of inhibitor formulation that is required to be added to each separately sourced batch of uncured concrete.
  • the inhibitor formulation is one selected to block and/or retard cement hydration.
  • the inhibitor formulation comprises one or more active ingredients selected from the group comprising citric acid monohydrate; lignosulphonates including calcium lignosulphonate, sodium lignosulphonate, and sugar-free lignosulphonates; hydroxycarboxylic acid and their salts; phosphonates; sugars (saccharides); phosphates; borates; and heavy metal salts.
  • the at least one characteristic of the specification or composition of the uncured concrete is the cement content of the uncured concrete.
  • the inhibitor formulation is added in an amount of % by weight based on the cement content of each separately sourced batch of uncured concrete (% BWOC).
  • the amount of inhibitor formulation to be added to each separately sourced batch of concrete will be calculated based on the total mass of the uncured concrete batch multiplied by the fraction of cement in the uncured concrete batch (or cement mass/total concrete mass).
  • a key aspect of the invention is the ability to produce a single batch of uncured concrete by aggregating residual or waste uncured concrete from multiple (two or more) sources.
  • the residual uncured concrete from each source is treated with a specific amount of an inhibitor formulation calculated to ensure that each batch is stabilized to the same level so that the combined concrete batch (or concrete aggregate) remains uncured for a specific or predetermined time period.
  • the predetermined time period can be determined based on when the concrete aggregate is going to be used. This allows for the reuse of residual uncured concrete from multiple sources in a variety of applications.
  • the invention resides in a method of reusing uncured concrete from more than one source, said method including the following steps: producing a batch of aggregated uncured concrete by the method described herein; using the aggregated uncured concrete in a concrete application or to make a concrete product.
  • an activator formulation may be added to the aggregated uncured concrete to advance the curing time of the aggregated uncured concrete.
  • the method comprises the step of identifying whether an activator formulation is required to be added to the aggregated uncured concrete.
  • this step is carried out by a computerized system.
  • the method includes the steps of: identifying at least one characteristic of the specification or composition of the aggregated uncured concrete; identifying the quantity of the aggregated uncured concrete; using this identified data to calculate a quantity of activator formulation to be added to the aggregated uncured concrete; mixing the calculated quantity of activator formulation with the aggregated uncured concrete.
  • these steps are carried out by a computerized system.
  • the concrete product is a precast or moulded concrete product, for example, a concrete block.
  • the invention resides in a precast concrete product made from an aggregated batch of uncured concrete produced by the method described herein.
  • the invention resides in a system for treating a batch of uncured concrete, the system comprising: a data input means adapted to allow input of data relating to the uncured concrete in the batch and/or a data retrieval means adapted to allow retrieval of data relating to the uncured concrete in the batch; a data transmitter adapted to transmit the data inputted and/or retrieved; a processor adapted to receive the data that is transmitted by the data transmitter and use at least that data to compute an amount of inhibitor formulation to be added to the uncured concrete to inhibit setting of the uncured concrete for a desired period of time; and a controller adapted to receive information regarding the computed amount of inhibitor formulation, and to allow the computed amount of inhibitor formulation to be dispensed to the uncured concrete.
  • the data that is inputted and/or retrieved includes at least one characteristic of the specification or composition of the batch of uncured concrete, the time that the batch of uncured concrete was produced, and the quantity of uncured concrete in the batch.
  • the data that is inputted and/or retrieved also includes the desired period of time that the uncured concrete is to remain inhibited or uncured.
  • the data that is inputted and/or retrieved further includes the following characteristics of the batch of uncured concrete: the water to cement ratio of the concrete batch, the sand to cement ratio of the concrete batch, and any additives present in the concrete batch.
  • the data retrieval means is in communication with a data storage means containing pre-determined data relating to the composition or specification of at least one type of uncured concrete mix.
  • the processor is adapted to compare data received from the data transmitter with the pre-determined data stored in the data storage means using a comparator, and use the result of the comparison to compute the amount of inhibitor formulation to be added to the uncured concrete.
  • the data storage means is located externally on a server or a cloud.
  • the system comprises a dispensing means adapted to store the inhibitor formulation, the dispensing means being in operative communication with the controller for allowing the computed amount of inhibitor formulation to be dispensed from the dispensing means to the uncured concrete.
  • the dispensing means comprises a valve that is in operative communication with the controller to perform a control action, the control action being opening of the valve to allow the computed amount of inhibitor formulation to be dispensed to the uncured concrete, and closing of the valve to prevent any further dispensing to the uncured concrete.
  • the system comprises a mixing or agitating means which is in operative communication with the controller for allowing the inhibitor formulation to be mixed or distributed through the uncured concrete.
  • the data input means is a manual data input means.
  • the data input means comprises an optical reader.
  • the data input means comprises a weight detector means.
  • the data input means comprises at least one sensor.
  • the system is housed on a vehicle that is carrying the batch of uncured concrete.
  • the system comprises means to monitor the quantity of discharge of the uncured concrete from the vehicle and/or the quantity of uncured concrete remaining in the vehicle.
  • the vehicle comprises means such as weighing means for measuring the quantity of uncured concrete loaded onto and/or remaining in the vehicle after discharge.
  • the invention relates to a vehicle comprising a system for treating a batch of uncured concrete as described herein.
  • the vehicle is a concrete mixer truck.
  • the system is located on a container or receiving unit that is to receive the batch of uncured concrete.
  • the container or receiving unit is located at a concrete manufacturing or batching plant, or at a concrete waste management facility.
  • the invention relates to a container or receiving unit comprising a system for treating a batch of uncured concrete as described herein.
  • the container or receiving unit comprises weighing means to measure the quantity of each batch of uncured concrete received by the container or receiving unit.
  • the container or receiving unit may include a mixing or agitating means to mix the contents of the receiving unit.
  • the container or receiving unit includes one or more sensors to measure one or more characteristics of the uncured concrete in the receiving unit.
  • the container or receiving unit has a lid.
  • the container or receiving unit includes a bar code or other tracking device to enable the effective management of the reuse of the uncured concrete received by the receiving unit.
  • the receiving unit includes at least one sensor means which is capable of monitoring the volume of uncured concrete in the receiving unit and transmitting a signal via the system indicating that the receiving unit is full to a desired level.
  • the invention resides in a system for treating a batch of aggregated uncured concrete, the system comprising: a data input means adapted to allow input of data relating to the aggregated uncured concrete and/or a data retrieval means adapted to retrieve data relating to the aggregated uncured concrete; a data transmitter adapted to transmit the data inputted and/or retrieved; a processor adapted to receive the data that is transmitted by the data transmitter and use at least that data to identify whether an amount of activator formulation is required to be added to the aggregated uncured concrete to advance the setting of the uncured concrete to a desired time; optionally computing an amount of activator formulation to be added to the uncured concrete; and a controller adapted to receive information regarding the computed amount of activator formulation, and to allow the computed amount of activator formulation to be dispensed to the aggregated uncured concrete if required.
  • the data that is inputted and/or retrieved includes at least the total mass of the batch of aggregated uncured concrete and the proportion of cement in the batch of
  • the activator formulation comprises one or more active ingredients selected from the group comprising aluminum salts, hydroxides, chlorides, bromides, fluorides, nitrites, nitrates, carbonates, thiocyanates, sulphates, thiosulphates, perchlorates, silicates, aluminates, carboxylic and hydroxycarboxylic acids and their salts, alkanolamines, aluminum sulphate, sodium thiocynate, and calcium chloride.
  • active ingredients selected from the group comprising aluminum salts, hydroxides, chlorides, bromides, fluorides, nitrites, nitrates, carbonates, thiocyanates, sulphates, thiosulphates, perchlorates, silicates, aluminates, carboxylic and hydroxycarboxylic acids and their salts, alkanolamines, aluminum sulphate, sodium thiocynate, and calcium chloride.
  • the activator formulation is added in an amount of % by weight based on the cement content of the batch of aggregated uncured concrete (% BWOC).
  • the data that is inputted and/or retrieved also includes the amount of water in the concrete aggregate, the amount of water reducer in the concrete aggregate, the sand content of the concrete aggregate, the density of the concrete aggregate, the amount of inhibitor formulation and the timing of addition of inhibitor formulation to each separately sourced batch of uncured concrete, and the weight ratio of each separately sourced batch of uncured concrete to the total amount of uncured concrete aggregate.
  • the data that is inputted and/or retrieved also includes the desired setting time of the aggregated uncured concrete.
  • the data retrieval means is in communication with a data storage means containing data relating to each batch of separately sourced uncured concrete that forms part of the batch of aggregated uncured concrete.
  • the processor is adapted to compare data received from the data transmitter with the pre-determined data stored in a data storage means using a comparator, and use the result of comparison to compute the amount of activator formulation to be added to the aggregated uncured concrete.
  • the data storage means is located externally on a server or a cloud.
  • the system comprises a dispensing means adapted to store the activator formulation, the dispensing means being in operative communication with the controller for allowing the computed amount of activator formulation to be dispensed from the dispensing means to the uncured concrete.
  • the dispensing means comprises a valve that is in operative communication with the controller to perform a control action, the control action being opening of the valve to allow the computed amount of activator formulation to be dispensed to the uncured concrete, and closing of the valve to prevent any further dispensing to the uncured concrete.
  • the system comprises a mixing or agitating means which is in operative communication with the controller for allowing the activator formulation to be mixed or distributed through the aggregated uncured concrete.
  • the data input means is a manual data input means.
  • the data input means comprises an optical reader.
  • the data input means comprises a weight detector means.
  • the data input means comprises at least one sensor.
  • the system is located on a vehicle or container or receiving unit that is adapted to pour or discharge the aggregated uncured concrete for reuse.
  • the processor is adapted to record the initial batching time of each batch of separately sourced uncured concrete received by a receiving unit and use that data to determine the priority of reuse of the uncured aggregated concrete in two or more receiving units.
  • Figure 1 is a flow chart depicting a method and/or system of treating a batch of uncured concrete in a mixer truck in accordance with a preferred embodiment of the invention.
  • Figure 2 is a flow chart depicting a method and/or system of collecting and treating a batch of uncured concrete in yard in accordance with a preferred embodiment of the invention.
  • Figure 3 is a flow chart depicting a method of reusing a batch of aggregated uncured concrete produced by the method of the invention in the manufacture of a precast concrete product in accordance with a preferred embodiment of the invention.
  • Figures 4 is a representation of a combined in-truck / in-yard method and/or system of treating and collecting a batch of uncured concrete in accordance with a preferred embodiment of the invention.
  • Figures 5 is a perspective view of an example of a receiving unit that may be used in the method of the invention.
  • Figure 6 is an end view of the receiving unit shown in Figure 5.
  • the invention relates generally to a method and/or system of collecting and treating waste or residual uncured concrete so that it can be reused in various applications, such as in the manufacture of valuable concrete products.
  • the method involves collecting residual uncured concrete from multiple (at least two) sources and treating each batch of uncured concrete with an inhibitor formulation to inhibit the curing or setting time of each batch of concrete for a predetermined time period to enable the separately sourced batches of uncured concrete to be combined into a single batch of uncured concrete or concrete aggregate for reuse in other applications.
  • the method and/or system of the invention includes at least the following steps: (1) identifying and/or recording the relevant properties (i.e. specification or composition) of a batch of uncured concrete; (2) identifying the time that the batch of uncured concrete was produced; (3) identifying the quantity of uncured concrete in the batch; (3) calculating the amount of inhibitor formulation required to inhibit the setting of the uncured concrete in the batch for a desired time period; and (4) mixing the calculated amount of inhibitor formulation into the batch of uncured concrete.
  • Steps (1) to (4) are carried out on separately sourced batches of uncured concrete, for example, the residual or waste concrete leftover from two or more jobs.
  • Each batch of treated (inhibited) concrete is combined with other batches of similarly treated (inhibited) concrete to produce a single batch of aggregated uncured concrete that can be reused in other applications.
  • each batch of uncured concrete may be carried out in-truck, for example in the concrete mixer truck itself, or in-yard, for example at a concrete manufacturing or batching plant, or a concrete waste management facility after the concrete mixer truck discharges its load, or by a combination of in-truck in-yard treatment.
  • the method preferably incorporates a computerised system which extracts and combines the necessary information and variables from the concrete manufacturing or batching plant and/or the mixer truck driver or other operators to determine the exact amount of inhibitor formulation that should be added to each batch of collected uncured concrete.
  • FIG. 1 a flow chart diagram is shown, depicting a method and/or system of treating a batch of uncured concrete in-truck or on-truck.
  • some of the method steps may be implemented in varying order depending on the given circumstances. Additionally, one or more method steps may be omitted under the appropriate circumstances.
  • the method and/or system includes at least the following steps.
  • the properties of the concrete mix being transported in the truck are recorded, preferably via a manual or automatic data input means. This can be done when the concrete mix is batched and loaded onto the mixer truck.
  • the recording step is done by a computerized system whereby users can input the relevant details of the concrete mix, i.e. its specification or composition, including for example, the water to cement ratio of the concrete mix, the sand to cement ratio of the concrete mix, any additives present in the concrete mix, the time the concrete mix is batched, the quantity of concrete batched and loaded onto the truck, the truck number, the job details and any other desired information.
  • Data can be input manually by way of a data input means, or alternatively the data relating to the composition or specification of the concrete mix could be retrieved from a database or data storage means (preferably located on an external server or cloud) comprising pre-determined data relating to the composition or specification of at least one type, but preferably multiple different types of uncured concrete mixes, for example, current commercially available concrete mixes.
  • This data could be stored in the data storage means by product or brand name for example.
  • the data retrieval means could then easily retrieve the composition details of a specific type of concrete mix by input of a keyword for example, a product name or part of a product name, and this data can then be transmitted to the system.
  • the truck driver is free to drive to the job site and start the job.
  • the computerized system may be able to monitor the concrete use during the job, for example, by on-truck sensor equipment which is capable of monitoring revolutions of the bowl when it is in discharge mode and feeding this information back to the computerized system so that the quantity of the concrete mix being discharged can be monitored. Whilst this is not an essential part of the method, it can help to determine when discharge of the concrete mix is complete and whether there is any residual concrete remaining in the mixer truck which is to be treated via the method of the invention.
  • the quantity of uncured concrete remaining in the drum of the mixer truck is determined (1 1).
  • the quantity of uncured concrete is preferably determined by weight. This may be accomplished by the use of a load cell or weighing means located between the hydraulic motor and chassis of the mixer truck.
  • a generally-automated machine can estimate the quantity of residual concrete based on one or more factors such as weight or torque loading on the hydraulic drive which rotates the mixing drum.
  • the amount of inhibitor formulation required to inhibit the setting of the concrete for a desired time period is calculated (12). This calculation is based on a combination of the parameters recorded in step 10 and the quantity data determined in step 1 1.
  • this calculation is carried out by a computerized system comprising one or more algorithms so that the calculation can be made automatically upon input or selection of the relevant variables by a user.
  • One of the data input variables is the desired time period, i.e. the desired length of time which the concrete should remain uncured for, which would be determined based on when the uncured concrete is likely to be used in another application in the future.
  • Other relevant data input variables may include the time that the concrete mix was initially batched (this information is preferably entered into the system at the time of batching) and the time that has lapsed since the concrete mix was batched.
  • the dosing or dispensing means may comprise for example a housing to hold the inhibitor formulation, which is connected by a pump and hose to the bowl of the mixer truck, and an activation system which can be activated by the controller of the computerized system or a driver or other user to dispense the calculated amount of the inhibitor formulation into the batch of uncured concrete.
  • the dispensing means may comprise a valve that is in operative communication with the controller to perform a control action, the control action being opening and closing of the valve to allow the calculated amount of inhibitor formulation to be dispensed to the uncured concrete.
  • the inhibitor formulation may be added directly to the mixer drum of the concrete truck at any time, for example, while the truck is still at the job site or while the truck is being driven back to the concrete batching plant or on route to a concrete waste management facility, or at the concrete batching plant or other facility.
  • the inhibitor formulation is preferably a formulation which blocks and/or retards cement hydration.
  • a preferred inhibitor formulation is commercially available under the brand name SikaTard-930 (manufactured by Sika (NZ) Limited). This is a liquid admixture, dosed as a percentage by weight of cement (BWOC) which inhibits the hydration of cement for up to three days.
  • BWOC percentage by weight of cement
  • the active ingredient in this inhibitor formulation is citric acid monohydrate.
  • Alternative inhibitor formulations can be used which may comprise one or more active ingredients selected from the group comprising citric acid monohydrate; lignosulphonates including calcium lignosulphonate, sodium lignosulphonate, and sugar-free lignosulphonates; hydroxycarboxylic acid and their salts; phosphonates; sugars (saccharides); phosphates; borates; and heavy metal salts.
  • active ingredients selected from the group comprising citric acid monohydrate; lignosulphonates including calcium lignosulphonate, sodium lignosulphonate, and sugar-free lignosulphonates; hydroxycarboxylic acid and their salts; phosphonates; sugars (saccharides); phosphates; borates; and heavy metal salts.
  • the inhibitor formulation is preferably added in an amount of % by weight based on the cement content of the concrete mix (% BWOC).
  • the amount of inhibitor formulation required may therefore be calculated based on the total mass of the batch of uncured concrete multiplied by the amount of cement in the concrete batch (or cement mass/total concrete mass).
  • the inhibitor formulation is added to the bowl of the mixer truck it is mixed (for example the bowl may be rotated or other mixing or agitating means may be employed) to enable distribution of the inhibitor formulation evenly through the uncured concrete.
  • Mixing may be by a combination of rapid mixing followed by more sedate mixing, whatever is required to achieve an even consistency or homogeneity of the mixture. It has been found that extended mixing or over-mixing may reduce the effectiveness of the inhibitor formulation so mixing should be stopped once the desired consistency and homogeneity of the mixture is reached.
  • the treated concrete can then be discharged from the truck into any conveniently located receiving unit (14).
  • the concrete manufacturing or batching plant may have one or more receiving units for receiving the batches of inhibited uncured concrete on return of the mixer trucks to the plant (see Figure 4 (30)).
  • one or more receiving units could be located at other facilities, for example, a concrete waste management facility.
  • the receiving unit may be any container capable of holding and storing uncured concrete.
  • the receiving unit may be for example a modified hopper or skip bin (see Figures 5 and 6).
  • the receiving unit may include an agitation means to mix the contents of the receiving unit, and one or more sensors to measure the quantity or other characteristics of the uncured concrete received by the receiving unit.
  • the receiving unit comprises a lid to avoid any contamination or degradation of the uncured concrete by air and/or UV light.
  • the minimum amount of inhibitor formulation is added to each batch of uncured concrete depending on how long it will be before the uncured concrete is reused. This will ensure that all of the uncured concrete from multiple sources that is received by the receiving unit is stabilised to the same level. This also ensures that the quality of the aggregated uncured concrete is maintained so that any products produced from the aggregated uncured concrete are consistent and stable and structurally sound.
  • the first batch of uncured concrete in the first truck discharging at time 0 should be dosed with the minimum amount of inhibitor formulation to inhibit the curing of the concrete for at least 12 hours, however if the next truck discharges its load at 0 + 6 hours, the uncured concrete in that load should be dosed with the minimum amount of inhibitor formulation required to inhibit the curing of the concrete for at least 6 hours, and if the final truck discharges at 0 + 9 hours, the uncured concrete in that load should only be dosed with an amount that will allow inhibition for at least 3 hours.
  • the receiving unit or the plant providing the receiving unit has a backup weighing system, for example, a load cell or weighing means located in, on or near the receiving unit which weighs the contents of the concrete truck mixer drum to confirm the exact quantity of inhibited uncured concrete that is being discharged (see Figure 4 at 32). More inhibitor formulation could then be added to the uncured concrete if required. Once it is confirmed that the uncured concrete is in the desired state, it is discharged into the receiving unit.
  • the receiving unit preferably includes sensors such as laser sensor devices which are capable of monitoring the volume of concrete in the receiving unit, so that when the receiving unit is full to a desired level, a signal is activated which shows that it is ready to be picked up (i.e.
  • the reuse of the uncured concrete aggregate may therefore take place at the same location as the receiving unit (for example a concrete waste management facility), or the receiving unit may be collected and transported to another location for further processing, for example, into value added products such as concrete blocks.
  • the computerised system is capable of logging all discharges of treated (inhibited) batches of uncured concrete into the receiving unit so that it is possible to determine the time of the oldest mix (by batching time) in the receiving unit to ensure that the further processing (i.e. reuse of the treated concrete aggregate) is carried out within the appropriate time parameters of the inhibited concrete aggregate.
  • the receiving unit may have a bar code or other tracking device so that each receiving unit is collected and/or processed in the desired order to ensure that the units containing the oldest mixes are given priority.
  • each batch of separately sourced uncured concrete could alternatively be carried out in-yard, for example at the concrete manufacturing or batching plant, or at any other desired location, for example, at a concrete waste management or reuse facility.
  • a flow chart diagram is shown, depicting a method for collecting and treating uncured concrete in-yard.
  • some of the method steps may be implemented in varying order depending on the given circumstances. Additionally, one or more method steps may be omitted under the appropriate circumstances.
  • the in-yard method shown in Figure 2 comprises essentially the same steps as the in-truck method of Figure 1, except that the dosing of the inhibitor formulation is done in a receiving unit located at the plant or other facility, instead of in the mixer truck.
  • This has the advantage of speeding up the processing of mixer trucks in a concrete batching facility by allowing the trucks to quickly discharge their residual uncured concrete loads and move on to receive another batch of fresh concrete for another job.
  • This method may involve the following steps. At 16, the mixer truck will discharge the batch of uncured concrete into the receiving unit. At 17, the properties of the concrete batch can either be recorded at the time of batching and loading as with the on-truck method of Figure 1, or the properties of the concrete batch can be recorded at the time of discharge into the receiving unit.
  • the quantity of residual concrete being discharged can either be measured and determined on-truck before discharge by weighing means as described in relation to the on-truck method, or the quantity of residual concrete can be determined after discharge into the receiving unit by load cells or weighing means located in, on or near the receiving unit (step 18).
  • the amount of inhibitor formulation required to be added to the uncured concrete is then calculated (19) preferably using a computerized system, as described in respect of the in-truck system, and then the calculated amount of inhibitor formulation is added to the receiving unit (20) either manually or automatically.
  • the receiving unit comprises an automatic dosing or dispensing system similar to that described in the on-truck method.
  • the receiving unit preferably has an agitation means to enable the inhibitor formulation to be mixed through the residual concrete.
  • a signal is issued via the computerized system to notify relevant parties that the receiving unit or storage unit is ready for collection, or that the aggregated uncured concrete in the receiving unit or storage unit is ready for reuse.
  • FIG. 4 shows a further example of how the method and/or system of the invention can be carried out in-truck in-yard.
  • a receiving unit (30) and associated computerized system (31) can be located at a facility such as a concrete batching plant or concrete waste management facility.
  • a concrete mixer truck containing residual uncured concrete for discharge can reverse up to the receiving unit (30), preferably onto a weighing means (32) (such as load cells) which will automatically weigh and calculate the quantity of uncured concrete in the load and transmit this data to the computerized system.
  • the computerized system may have a data input and/or retrieval means (33) located by the driver's window so that the driver can input and/or retrieve any required data relating to the composition of the uncured concrete in the load and any other relevant information.
  • the data that is inputted and/or retrieved could include at least one characteristic of the specification or composition of the batch of uncured concrete (such as the water to cement ratio of the concrete batch, the sand to cement ratio of the concrete batch, and any additives present in the concrete batch), the time that the batch of uncured concrete was produced, the quantity of uncured concrete in the batch, the desired period of time that the uncured concrete is to remain inhibited or uncured.
  • Some or all of this information could be retrieved by the computerized system from data that has already been entered into the system and is stored in a data storage means (preferably located on an external server or cloud).
  • the data input means (33) is preferably operatively connected to a dispensing means (34).
  • the system (31) may therefore comprise a data transmitter for transmitting the data inputted and/or retrieved via the data input and/or retrieval means (33), a processor for receiving the data from the data transmitter and using at least that data to compute or calculate an amount of inhibitor formulation to be added to the uncured concrete load to inhibit the setting time of the uncured concrete for a desired period of time, and a controller which receives the information regarding the amount of inhibitor formulation to be added to the uncured concrete load and activates the dispensing means (34) to dispense the calculated amount of inhibitor formulation to the uncured concrete.
  • the dispensing means comprises a housing (35) for holding the inhibitor formulation, and a pump and hose assembly (36) for dispensing the inhibitor formulation.
  • the system calculates the amount of inhibitor formulation required based on the inputted and/or retrieved data regarding the properties and desired reuse parameters of the uncured concrete in the load, and the quantity of uncured concrete determined by the weighing means (32) (or this information could also be retrieved from prior entered data), and then adds the calculated quantity of inhibitor formulation to the mixing bowl located on the mixing truck.
  • the inhibitor formulation can be mixed through the uncured concrete either by rotating the bowl of the truck or by a separate mixing or agitation means.
  • the treated uncured concrete is then discharged into the receiving unit (30). It is envisaged that different types of uncured concrete with different compositions and different batching times can be aggregated together by the method of the invention without compromising the structural integrity of the concrete once it has cured. However preferably the aggregated uncured concrete is tested for quality and graded for its strength and structural properties so that it can be used in specific applications depending on its characteristics.
  • the aggregated uncured concrete could be used in a variety of applications, or to manufacture a variety of valuable concrete products, such as precast concrete products.
  • FIG. 3 a flow chart diagram is shown, depicting an example of reuse of a batch of aggregated uncured concrete produced by the method of the invention in the manufacture of a precast concrete product.
  • some of the method steps may be implemented in varying order depending on the given circumstances. Additionally, one or more method steps may be omitted under the appropriate circumstances.
  • the method involves the following steps. At 21, one or more batches of aggregated uncured concrete are collected from one or more receiving units. The state and properties of each batch of aggregated uncured concrete can then be measured to determine how far it is away from setting or curing (22). The measurement of these properties can be done manually or automatically by way of a computerized system which is able to access data relating to each batch of aggregated uncured concrete. If necessary, an activator formulation can be added to the aggregated uncured concrete to increase the setting time. The activator formulation essentially neutralizes the effects of the inhibitor formulation. For example, an activator formulation can be added to the aggregated uncured concrete if it was desired to move the curing time of the concrete forward.
  • the amount of activator formulation is calculated (23) based on the identified properties of the aggregated uncured concrete, the quantity of the aggregated uncured concrete, and the desired curing time.
  • the calculation is performed by a computerized system which may operate in a similar way as the computerized system used to calculate the amount of inhibitor formulation to be added to each separately sourced batch of uncured concrete.
  • the computerized system may have a data input means and/or data retrieval means so that data can be inputted and/or retrieved regarding the details of the aggregated uncured concrete batch, such as the amount of cement in the concrete aggregate, the amount of water in the concrete aggregate, the amount of water reducer in the concrete aggregate, the sand content of the concrete aggregate, the density of the concrete aggregate, the amount of inhibitor formulation and the timing of addition of inhibitor formulation to each batch of uncured concrete within the concrete aggregate, and the weight ratio of each separately sourced batch of uncured concrete within the concrete aggregate to the total amount of aggregated uncured concrete, and the desired setting time of the aggregated uncured concrete.
  • the details of the aggregated uncured concrete batch such as the amount of cement in the concrete aggregate, the amount of water in the concrete aggregate, the amount of water reducer in the concrete aggregate, the sand content of the concrete aggregate, the density of the concrete aggregate, the amount of inhibitor formulation and the timing of addition of inhibitor formulation to each batch of uncured concrete within the concrete aggregate, and the weight ratio of each separately sourced batch of un
  • the data input means and/or data retrieval means is preferably operatively connected to a dispensing means.
  • the system therefore may comprise a data transmitter for transmitting the data inputted and/or retrieved, a processor for receiving the data from the data transmitter and using at least that data to compute or calculate an amount of activator formulation to be added to the aggregated uncured concrete to advance the setting time of the uncured concrete to a desired time, and a controller which receives the information regarding the amount of activator formulation to be added to the aggregated uncured concrete and activates the dispensing means to dispense the calculated amount of activator formulation to the aggregated uncured concrete.
  • the dispensing means comprises a housing for holding the activator formulation, and a pump and hose assembly or valve assembly for dispensing the activator formulation. The system calculates the amount of activator formulation required based on the inputted and/or retrieved data regarding the aggregated uncured concrete in the batch, and the quantity of aggregated uncured concrete, and the desired curing time.
  • activator formulation Any activator formulation known in the art can be used.
  • a preferred activator formulation is commercially available under the brand name Sigunit-L53 AF (manufactured by Sika (NZ) Limited). This is a liquid accelerator shotcrete admixture, usually dosed as a percentage by weight of binder (BWOB) which is designed to overcome the high strength inhibition of the SikaTard-930 inhibitor formulation.
  • BWOB binder
  • the active ingredient of this formulation is aluminum salts.
  • Alternative activator formulations can be used which comprise one or more active ingredients selected from the group comprising aluminum salts, hydroxides, chlorides, bromides, fluorides, nitrites, nitrates, carbonates, thiocyanates, sulphates, thiosulphates, perchlorates, silicates, aluminates, carboxylic and hydroxycarboxylic acids and their salts, alkanolamines, aluminum sulphate, sodium thiocynate, calcium chloride.
  • active ingredients selected from the group comprising aluminum salts, hydroxides, chlorides, bromides, fluorides, nitrites, nitrates, carbonates, thiocyanates, sulphates, thiosulphates, perchlorates, silicates, aluminates, carboxylic and hydroxycarboxylic acids and their salts, alkanolamines, aluminum sulphate, sodium thiocynate, calcium chloride.
  • Dosing BWOB assumes that the activator formulation will be used with one type of concrete with a constant cement content, however given that the method of the invention collects and treats a variety of different types of concrete from multiple sources, the activator is preferably dosed BWOC for consistency and transferability across a range of concrete mixes.
  • the amount of activator formulation to be added may therefore be based on the total mass of the aggregated uncured concrete multiplied by the fraction of cement in the aggregated uncured concrete (or cement mass/total concrete mass).
  • the amount of activator formulation required is calculated, it is added to the aggregated uncured concrete (24) and mixed to enable distribution of the activator formulation evenly through the uncured concrete.
  • Mixing may be by a combination of rapid mixing followed by more sedate mixing, whatever is required to achieve an even consistency or homogeneity of the mixture.
  • the concrete is dispensed into moulds (25).
  • the moulds may either be stationary, in which case the concrete is dispensed from a concrete truck, or the moulds may run on moving rails underneath a hopper or receiving unit that has been adapted to hold and dispense the concrete.
  • the same receiving unit used to collect and aggregate the separate batches of uncured concrete could be used to dispense the aggregated uncured concrete into the moulds.
  • this step may need to be carried out quickly so that the concrete remains in a suitable consistency for pouring into the moulds.
  • the moulds may then be put through a vibrating and/or screening step to remove any air pockets within the concrete, and then they are transferred to a curing bay for drying/curing.
  • precast concrete product that can be made is an interlocking concrete block for building. These types of blocks are usually cured for about 12 hours before de- moulding. They are then stored for about 28 days for full curing to take place. Concrete blocks produced by this method are preferably tested for compressive strength and structural integrity so they can be graded accordingly and labeled for specific uses or applications.
  • the applicant has conducted extensive research into the behavior of many different types of commercially available concrete mixes in New Zealand, to determine optimum dosing levels of inhibitor formulation and activator formulation (if required) for use in the method and/or system of the invention. Vicat setting time tests and compressive strength tests were conducted, with the results analysed by mathematical modelling to produce algorithms for concretes of any design to be inhibited and activated. Additional testing was then conducted to improve the accuracy of the algorithms and target the desired inhibition and activation times.
  • the R Project software package and the ACE fitting procedure were used to build a predictive model of the range of concretes maximum time remains inhibited (mTRI) and the time to set (TTS) for inhibitor and activator dosages and timings which allows for the prediction of the correct inhibitor and activator dosage to meet the desired specifications for a given concrete.
  • the first step in the calculation is to calculate the inhibitor dosage (ID) using the following equation:
  • TIA is the known or expected time (in decimal hours) that has elapsed since the initial batch mixing of the concrete and the time that the inhibitor formulation will be added.
  • i(ID) 1.072916 - 3.544532 x e (_1 542257 x ID)
  • the next step in the calculation is to enter i(ID) in the following equation, along with the water to cement ratio (W:C) and sand to cement ratio (S:C) of the concrete batch:
  • In(mTRI) 4.1 147 + 0.9844 x i(ID) + 0.8728 x W:C - 0.3641 x S:C wherein mTRI is the maximum inhibition time of a concrete before it eventually sets without activation, measured from the point of TIA.
  • this ID can be used to calculate the amount of inhibitor formulation to be used as a % BWOC (by weight of cement).
  • the amount of inhibitor formulation to use in % BWOC will be:
  • the desired mTRI can be entered into the above equation to solve for ID.
  • the next step in the calculation is to enter a(ID) in the following equation, along with the water to cement ratio (W:C) and sand to cement ratio (S:C) and the desired time to set (TTS) of the concrete batch, and solve for AD:
  • TTS is the time an activated concrete takes to set, measured from the point of TAA which is measured in decimal hours based on the time that has elapsed between the time that the inhibitor formulation was added to the concrete batch (TIA) and the time when the activator formulation is or is expected to be added.
  • the calculated AD can be used to calculate the amount of activator formulation to be used as a % BWOC (by weight of cement).
  • the amount of activator formulation to use in % BWOC will be:
  • the above calculations are made automatically by a computerized system with the input of the relevant variables.
  • the activation algorithm could be modified if required to take into account the varying levels of cement content and inhibitor formulation present in each single batch of concrete that has been combined to form the aggregated batch of inhibited concrete.
  • the invention provides for an improved method and/or system for the reuse of residual uncured concrete.
  • the invention is designed to stop the uncured concrete setting process for a sufficient period of time to enable multiple batches of uncured concrete from multiple sources to be combined into a single aggregated batch of uncured concrete which can then be reused in any number of applications, for example, in the manufacture of value-added concrete products.
  • the advantages of the invention are many.
  • the useable life of the uncured concrete is greatly extended, and the method enables the life of the concrete to be effectively managed so that it is not wasted and is instead used in other valuable applications.
  • the effective management of the concrete enables different compositions of uncured concrete to be collected from multiple sources and from a wide geographical area thereby allowing for greater economies of scale.
  • Truck movements can be managed effectively and efficiently by a computerized system.
  • Advantages in cost savings will be realised by concrete manufacturing and batching plants who will no longer have to pay expensive waste concrete disposal costs.
  • Environmental advantages will be realised by all since the large amount of residual uncured concrete that is currently disposed of in landfills will instead be used in valuable applications or be used to make valuable products.
  • the strength and structural integrity of concrete products made with aggregated uncured concrete produced by the method of the invention have been shown not to have been significantly compromised. In fact, the concrete products produced are generally consistent and stable products which are of high quality and structurally sound.
  • Example 2 While an example of a manual calculation for calculating the dosage quantities of inhibitor and activator formulation has been provided in Example 2, it is possible for other calculations and/or algorithms to be used in the method and/or system of the invention that have been generated by other types of mathematical modelling methods and/or programs and/or software. It is envisaged that various computerized systems could be used in the method and/or system of the invention that provide the same or similar functions to achieve the same or similar general purpose and/or outcome.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Inorganic Chemistry (AREA)
  • Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)

Abstract

L'invention concerne un procédé et/ou un système de collecte et de traitement de déchets ou de résidus de béton non durci de sorte qu'il peut être réutilisé dans diverses applications. De façon générale, le procédé consiste à collecter des résidus de béton non durci provenant de multiples sources et à traiter chaque lot de béton non durci avec une quantité calculée d'une formulation d'inhibiteur afin d'inhiber le durcissement ou le temps de prise du lot pendant une période de temps prédéterminée afin de permettre aux lots de béton non durci fournis séparément d'être combinés en un lot unique agrégé de béton non durci pour une réutilisation. L'invention permet d'agréger des résidus ou déchets de béton non durci provenant de multiples tâches ou de multiples sources et de le stabiliser au même niveau de sorte que le lot combiné reste non durci pendant la période de temps souhaitée afin de permettre la réutilisation efficace du béton autrement perdu. Le lot agrégé de béton non durci peut être traité avec une quantité calculée d'une formulation d'activateur pour accélérer le temps de prise du lot selon les besoins pour sa réutilisation.
PCT/NZ2018/050049 2017-04-12 2018-04-11 Procédé et/ou système de traitement et/ou de réutilisation de béton non durci Ceased WO2018190730A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11295248B2 (en) 2019-08-01 2022-04-05 Gcp Applied Technologies Inc. Coordinating concrete delivery and placement

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19518469A1 (de) * 1995-05-19 1996-11-28 Sandoz Ag Wiederverwendung von Restbeton
WO2016071298A1 (fr) * 2014-11-07 2016-05-12 Sika Technology Ag Procédé de fabrication de granulés à partir de compositions à base de ciment

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19518469A1 (de) * 1995-05-19 1996-11-28 Sandoz Ag Wiederverwendung von Restbeton
WO2016071298A1 (fr) * 2014-11-07 2016-05-12 Sika Technology Ag Procédé de fabrication de granulés à partir de compositions à base de ciment

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11295248B2 (en) 2019-08-01 2022-04-05 Gcp Applied Technologies Inc. Coordinating concrete delivery and placement
US20220180270A1 (en) * 2019-08-01 2022-06-09 Gcp Applied Technologies Inc. Concrete Placement Sensing Using Aerial Drones
US12106237B2 (en) 2019-08-01 2024-10-01 Gcp Applied Technologies Inc. Concrete placement sensing using aerial drones

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