AU2019203501A1 - Fast hardening, early light loading and surface cracking resistance concrete - Google Patents

Abstract

The invention relates to fast hardening, early light loading and surface cracking resistance concrete, which is mixed with water to maintain good workability, develop early strength and high end strength (R-28). Material composition of concrete according to the invention is as follows: Item Percent (%) River Sand 20-25% Crush Sand 12-16% Stone 5 x 10 40-50% Cement OPC 18-22% High alumina cement 1.5-2% Fiber 0.01-1% Powercon 100 0.01-1% Lithium Carbonate 0.01-1% Sodium Gluconate 0.01-1% Esapor 1850-C 0.01-1% Other additives 0.01-1% 1

Description

FAST HARDENING, EARLY LIGHT LOADING AND SURFACE CRACKING RESISTANCE CONCRETE

Technical Field The invention relates to fast hardening, early light loading and surface cracking resistance concrete, which is mixed with water to maintain good workability, develop early strength and high end strength (R-28).

Background Concrete (derived from the French word "bton") is an artificial stone, formed by mixing ingredients: Light aggregates, fine aggregates, adhesives, etc. with a certain percentage (which is called concrete aggregation). In concrete, adhesives (cement mixed with water, additive etc.) as a linkage of light aggregates (stone, gravel, etc. sometimes using synthetic materials in lightweight concrete) and fine aggregate (usually sand, grit, grindstone, etc.) and when solidified, make all a solid block like stone.

At present, concrete is quite popular material in construction works. There are many different types of concrete. They are classified by weight, adhesive type, structure, technological characteristics and scope of use.

Concrete on the market today often has horizontal cracking, plastic cracking after a period of use for the following reasons: - Concrete is mixed with too much water. - Expansion joint is not effective. - The concrete pouring distance is too large, leading to a long hardening time, from several weeks to several months. - Cold weather, concrete surface lacks proper air void system, low-quality raw aggregate. - The durability of concrete is not high due to the design and operation process, climatic conditions, environment related to the structure.

- Cracks can often be seen when bending stress is greater than that of concrete.

Concrete on the market has a hardening process as following:

• Casting stage takes from 1.5 to 3 hours for conventional concrete and 3-4 hours for concrete with slow curing additives. • Curing and hardening stage is from 18-24 hours after the beginning of curing. • Developing intensity of concrete structure stage.

Summary

The present invention relates to fast hardening, early light loading and surface cracking resistance concrete, which is mixed and packed in accordance with standards, which is usable only by adding water, easy for use or repair in civil construction, in a small or medium area and it is considered as a do-it-yourself product.

The concrete according to the invention has high flexibility in construction, maintains its construction and repair capacity within 1 hour. Users can do in a large area without separating the layer as well as creating a connection layer. The concrete develops strength rapidly and it is able to withstand light loads after 4 hours, a person can walk on the surface. This saves a lot of construction time and improves economic efficiency. It is unnecessary to wait 24 hours for using as available concretes in the market.

High end strength R28 reaches resistance grade above 50MPa, has the good compacting capacity, leading to high waterproofing, the product is suitable for many civil and industrial construction applications.

After developing the strength of concrete, there is no cracking surface, with higher stretch, bending capacity than conventional concrete, bringing economic value and safety for solid structures.

Detailed Description The present invention relates to fast hardening, early light loading and surface cracking resistance concrete, which is mixed and packed in accordance with standards, which is usable only by adding water, easy for use or repair in civil construction, in a small or medium area and it is considered as a do-it-yourself product.

The material composition of concrete according to the invention is as follows:

Item Percent (%)

River Sand 20-25%

Crush Sand 12-16%

Stone 5 x 10 mm 40-50%

Cement OPC 18-22%

High Alumina Cement 1.5-2%

Fiber 0.01-1%

Powercon 100 0.01-1%

Lithium Carbonate 0.01-1%

Sodium Gluconate 0.01-1%

Esapor 1850-C 0.01-1%

Other additives 0.01-1%

The concrete according to the invention has high flexibility in construction, maintains its construction and repair capacity within 1 hour. Users can do in a large area without separating the layer as well as creating a connection layer. The concrete develops strength rapidly and it is able to withstand light loads after 4 hours, a person can walk on the surface. This saves a lot of construction time and improves economic efficiency. It is unnecessary to wait 24 hours for using as available concretes in the market. High end strength R28 reaches resistance grade above 50MPa, has a good compacting capacity, leading to high waterproofing, the product is suitable for many civil and industrial construction applications. Said early and end strength, according to ASTM C-349 standard, is R21 and R28 strength. Under civil concrete, R21 and R28 strength have resistance grade of 5MPa and 25MPa respectively. The higher the concrete resistance, the more compact capacity. This means that concrete has few tiny hollow pores that prevent water from passing through the concrete. This is called the waterproofing mechanism by the consistency of concrete blocks. After developing the strength of concrete, there is no cracking surface, with higher stretch, bending capacity than conventional concrete, bringing economic value and safety for solid structures. In order to obtain the optimal performance according to the present invention, concrete is formed based on the selected materials, in details: - Sand and crushed stone, stones are selected in size so that the products can obtain the optimal properties mentioned above, with light foamed, high flexibility of concrete. - Cement used in concrete is Portland OPC cement with good properties of high strength and abrasion resistance. - The additive used has super plasticizing properties, has fibers to increase the resistance to cracking and has substances that promote the development of early strength without affecting the construction time of the product.

Effectiveness of the invention The concrete according to the invention has high flexibility in construction, maintains its construction and repair capacity within 1 hour. Users can do in a large area without separating the layer as well as creating a connection layer. The concrete develops strength rapidly and it is able to withstand light loads after 4 hours, a person can walk on the surface.

High end strength R28 reaches resistance grade above 50MPa, has a good compacting capacity, leading to high waterproofing, the product is suitable for many civil and industrial construction applications.

Besides, after developing the strength of concrete, there is no cracking surface, with higher stretch, bending capacity than conventional concrete, bringing economic value and safety for solid structures.

Concrete according to the invention have advantages in compare with common types of concrete as follows:

Content Concrete according to the Other concrete invention

Hardening time 4 hours 18 - 24 hours

End strength (R28) > 50MPa 25MPa

Bending strength 6.8MPa 3.99MPa

Water/Concrete rate 0.51% 0.67%

EDITORIAL NOTE

2019203501

There is one page of the claims only.

Claims (3)

1. Claims 1. Fast hardening, early light loading and surface cracking resistance concrete, comprises:

   Item Percent(%)

   River Sand 20-25%

   Crush Sand 12-16%

   Stone 5 x 10 40-50%

   Cement OPC 18-22%

   High alumina cement 1.5-2%

   Fiber 0.01-1%

   Powercon 100 0.01-1%

   Lithium Carbonate 0.01-1%

   Sodium Gluconate 0.01-1%

   Esapor 1850-C 0.01-1%

   Other additives 0.01-1%
2. 2. Concrete of claim 1, wherein sand and crushed stone are selected in size so that the products can obtain the optimal properties mentioned above with high end strength (> 50MPa).
3. 3. Concrete of claim 1, wherein cement is Portland OPC cement with good properties of high strenth and abrasion resistance.