CN103058541A - Application of Graphene Oxide as Early Strength Enhancer of Cement - Google Patents

Abstract

The invention relates to application of graphene oxide as a cement early strength reinforcing agent, and belongs to the field of building materials. The invention provides an application of graphene oxide as a cement early strength reinforcing agent. The graphene oxide is a nano-scale high polymer material, can fill micro gaps among cement particles, enables a cement microstructure to be dense and flat, has high surface activity, can promote a hydration process of cement, and effectively improves mechanical properties of the cement.

Description

Application of Graphene Oxide as Early Strength Enhancer of Cement

technical field

The invention relates to the application of graphene oxide as an early strength enhancer of cement, belonging to the field of building materials.

Background technique

Cement-based materials are widely used in infrastructure such as houses, bridges, and coastal dams. However, with the development of economic construction, higher requirements are placed on the performance of cement-based materials; The erosion of harmful substances will inevitably lead to the degradation of the performance of cement-based materials, resulting in initial damage to the structure, which directly affects the durability of the structure. How to improve the early performance (mechanical properties, durability) of cement-based materials is of great significance to improve the durability of concrete structures, and related research has gradually attracted the attention of civil engineering circles at home and abroad.

Graphene oxide has very excellent properties. It not only has good wetting properties and surface activity, but also can be exfoliated after intercalation by small molecules or polymers. It plays a very important role in improving the comprehensive properties of materials such as thermal, electrical, and mechanical properties. important role. The excellent properties of graphene oxide provide a new research direction for improving the early performance of cement-based materials, but there is no research report on the performance of graphene oxide-modified cement-based materials in the existing research. In view of the above problems, research on graphene oxide The effect on cement strength is very necessary.

Contents of the invention

In view of the above problems, the purpose of the present invention is to provide a method for improving the early strength of cement by using graphene oxide, so as to solve the problem of reduced structural durability due to the low early performance of ordinary cement-based materials.

The technical scheme that the present invention solves the problem is:

Application of graphene oxide as cement early strength enhancer.

Graphene oxide is a nano-scale polymer material, which can not only fill the tiny gaps between cement particles, make the cement microstructure dense and smooth, graphene oxide also has high surface activity, can promote the hydration process of cement, and improve the cement. mechanical properties.

The graphene oxide described in the present invention is preferably graphene oxide with a monolayer content of more than 99% after dissolution and a graphene oxide purity greater than 99%.

The graphene oxide described in the present invention preferably has a particle diameter of 1-5 μm and a thickness of 0.8-1.2 nm.

Another object of the present invention is to provide a graphene oxide modified cement.

A graphene oxide modified cement, the modified cement is composed of ordinary cement and graphene oxide, and the graphene oxide accounts for 0.05% of the total mass of the modified cement.

A method for preparing modified cement mortar, comprising a pretreatment step of graphene oxide, wherein the pretreatment step is ultrasonically dispersing graphene oxide in deionized water and simultaneously stirring for at least 3 hours.

Preferably, the pretreatment step of the above-mentioned preparation method of modified cement mortar is ultrasonically dispersing graphene oxide in deionized water and simultaneously stirring for 3 hours.

The preparation method of cement mortar of the present invention preferably mixes the graphene oxide obtained through the pretreatment step with ordinary cement, and then prepares the graphene oxide cement mortar test piece according to the preparation method of the cement test piece in the prior art, and the test piece After preparation, put it into a standard curing box (temperature 20±1°C, relative humidity ≥95%) for curing, remove the mold after 1 day and continue curing in the standard curing box to the set age, and you can get early strength improvement. cement test piece.

The beneficial effects of the present invention are: the present invention uses the traditional mixing method to prepare graphene oxide cement specimens, the mixing process is simple, the amount of graphene oxide is less, and the early strength of cement can be significantly improved, and the early damage of cement can be reduced , providing a new research direction for improving the durability of cement-based materials.

Description of drawings

4 pieces of accompanying drawings of the present invention,

Fig. 1 is the SEM photograph of graphene oxide used in embodiment 1;

Fig. 2 is the TEM photograph of graphene oxide used in embodiment 1;

Fig. 3 is the 3 days curing age flexural strength of the different cement specimens of embodiment 1;

Fig. 4 is the 3-day curing age compressive strength of different cement specimens in Example 1.

Detailed ways

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

Graphene oxide was produced by Nanjing Xianfeng Nano Material Technology Co., Ltd.

Example 1

(1) Raw materials

Graphene oxide used in the present embodiment has a particle diameter of 1 to 5 microns and a thickness of 0.8 to 1.2 nanometers. The microscopic appearance under the scanning electron microscope (SEM) and the microscopic appearance under the transmission electron microscope (TEM) are as shown in Figure 1 and As shown in Figure 2,

(2) The mixing ratio of ordinary cement specimens and graphene oxide modified cement specimens is shown in Table 1.

Table 1 Grouping of cement specimens

In the test, the water-binder ratio of the cement specimen was 0.5, and the graphene oxide was weighed according to 0.05% of the mass of the modified cement with a high-precision balance, and then the graphene oxide was ultrasonically dispersed in deionized water for 3 hours and stirred with a glass rod, ultrasonically The power is 300W (DS-5510DTH type ultrasonic cleaning machine), and then prepare graphene oxide cement specimen according to the preparation method of ordinary cement specimen in China's current standard "Highway Engineering Cement and Cement Concrete Test Regulations" (JTG E30-2005), After the specimens are prepared, put them in a standard curing box (temperature 20±1°C, relative humidity ≥95%) for curing, remove the mold after 1 day and continue curing in the standard curing box until 3 days old. After curing to the test age, take out the cement specimen, and test its flexural strength and compressive strength with a flexural testing machine and a pressure testing machine (YAW-YAW2000A 200t microcomputer-controlled electro-hydraulic servo pressure testing machine). The specific test data As shown in Table 2, Figure 3 and Figure 4.

Table 2 Strength comparison of ordinary cement and graphene oxide modified cement specimens in 3 days

From the data in Table 2 and Figures 3 and 4, it can be seen that graphene oxide can significantly increase the 3-day flexural compressive strength of cement, in which the flexural strength increased by 19.70%, and the compressive strength increased by 27.00%.

Therefore, we can conclude that adding a small amount of graphene oxide to cement can significantly improve the early strength of cement.

Claims (5)

1. The application of graphene oxide as early strength enhancer of cement. 2. The application according to claim 1, characterized in that: the particle diameter of the graphene oxide is 1-5 μm, and the thickness is 0.8-1.2 nm. 3. A graphene oxide modified cement, characterized in that: the modified cement is composed of ordinary cement and graphene oxide, and graphene oxide accounts for 0.05% of the total mass of the modified cement. 4. a preparation method of graphene oxide modified cement mortar, is characterized in that: comprise the step of graphene oxide pretreatment, the step of described pretreatment is that graphene oxide is ultrasonically dispersed in deionized water and stirred at least simultaneously 3h. 5. The method according to claim 4, characterized in that: the pretreatment step is to ultrasonically disperse graphene oxide in deionized water while stirring for 3h.

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