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Raw Material High Strength, Long Durability
Jul 19, 2017

Raw Material High performance concrete composition materials are: cement, water, coarse aggregate, fine aggregate and, if necessary, the incorporation of mineral superfine powder and admixture.

(1) cement

In addition to the cement label, the composition and fineness of the cement minerals have an impact on the performance of high performance concrete. Generally speaking, the preparation of high-performance concrete cement, the content (mass fraction) should be low (generally should not exceed the cement in the free calcium oxide, magnesium oxide and sulfur trioxide and other harmful ingredients should be as little as possible. The strength of the early growth is fast, but the late strength increase less, and the hydration heat,Raw Material so the fineness should be appropriate. High performance concrete To ensure its high mobility, high strength, high durability, cement must be used with the superplasticizer Good compatibility, so that concrete mix in the working conditions to meet the water as low as possible, the width of the small loss.

(2) mineral admixtures

Ultra-fine powder in the concrete high strength, long durability played an important role. Ultra-fine powder as a cement-based composite material of the active admixture, can reduce the heat of hydration heat and hydration heat release rate, improve workability, enhance the late strength, improve the internal structure, improve the anti-corrosive ability, The powder can make the pore structure in the porous cementitious material thinner and not connect, reduce the porosity, and reduce the unfavorable component of calcium hydroxide in the cement hydration product to produce more favorable hydrated calcium silicate, thus Improve the performance of cement-based materials. The effect of admixtures on the strength of high performance concrete is very important. Adhesives of different proportions and types have great influence on the strength. The study on the mechanical properties of concrete with mixed mineral admixture shows that the incorporation of mineral admixtures such as slag, fly ash and silica fume has a certain effect on the performance of concrete, but its effect may not be positive. In the case of single admixture,Raw Material slag and silica fume can effectively improve the cohesion of the mixture, thus improving the early and late strength of concrete, but the mixture has a certain impact on the mobility; mixed fly ash can effectively improve Fluidity, but the production of bleeding on the homogeneity of the mixture has a negative impact, and because the fly ash ash reaction at room temperature for relatively slow, so the early strength of concrete is low. In the case of double admixture and triple admixture, the interaction effect of volcanic ash and composite effect of micro aggregate can occur in the composite material.

(3) admixture

Admixture is a key factor in the preparation of high performance concrete. When the adaptability of the admixture is better than that of the cement, the working performance of the new concrete is obviously improved, and the concrete coagulation time can be effectively controlled according to the needs. The loss of the Dan degree is small, the concrete density is good and the strength of each age is larger Of the increase in durability of concrete indicators have greatly improved. Ordinary water-reducing agent in the normal amount of water reduction rate,Raw Material the amount is too large will lead to excessive retardation or segregation and other fault phenomena. High performance concrete is associated with high dose of superplasticizer. The amount of superplasticizer (the amount of cementitious material) is generally. Because high-performance concrete is generally low water-cement ratio and low water consumption, in some cases, the increase in concrete slump is to increase the amount of superplasticizer to achieve.

(4) Aggregate

High-performance concrete than ordinary concrete strength, water consumption, the nature of aggregate on the strength of concrete, work has a greater impact. Ordinary concrete should increase the maximum particle size of coarse aggregate to a certain extent to improve the workability and strength of concrete. But for high-performance concrete should use the largest particle size of the aggregate,Raw Material because the aggregate size will increase the performance of concrete. Excellent aggregate gradation is an important factor in saving cement and ensuring good workability of concrete.

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