High-early-strength mineral additive for concrete

Abstract

The invention relates to a high-early-strength mineral additive for concrete, which is characterized in that the high-early-strength mineral additive consists of the following ingredients which are mixed by mass percent: 30-50 percent of mineral powder, 20-35 percent of pulverized coal ash, 5-15 percent of silicon ash, 5-15 percent of metakaolin, 2-5 percent of sodium sulfate and 1-2 percent of polycarboxylate water reducing agent The high-early-strength mineral additive provided by the invention can be used for concrete prefabricated members, grouting materials, patching materials and the like. When 10 percent of high-early-strength mineral additive is added to replace cement to prepare the concrete, the water demand is small, the early activity index is high, the strength development situation is good, and compared with common cement and mineral additives, the dry shrinkage resistance is improved greatly.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to a high-early-strength mineral admixture for concrete. Background technique [0002] With the development of highways, railways, ports, aviation and urban construction, high-performance concrete technology has become the demand and development direction of modern engineering. Using slag powder, fly ash, silica fume, etc. as mineral admixtures to replace part of cement to prepare mortar or concrete can not only reduce resource consumption, reduce the economic cost of concrete, but also improve the performance of concrete in terms of work, mechanics and durability. Mineral admixtures have become an indispensable and important part of high performance concrete. [0003] However, in the actual engineering application process, it is found that the commonly used mineral admixtures have the following problems: First, mineral admixtures such as mineral powder and fly ash repla...

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Problems solved by technology

[0003] However, in the actual engineering application process, it is found that the commonly used mineral admixtures have the following problems: First, mineral admixtures such as mineral powder and fly ash replace part of the cement to prepare mortar or concrete, and the setting time will be prolonged. Problems such as low strength and slow strength development affect the demoulding time, delay the construction period, and fail to meet the requirements of rapid construction; second, although silica fume and other mineral admixtures have high activity, they can theoretically improve the early and late strength of concrete. However, due to its large specific surface area and high water demand, in order to ensure the working performance of mortar or concrete, more water is often added during use to increase the water-binder ratio, which reduces the strength of mortar or concrete.

[0004] The mechanism of action of different mineral admixtures in concrete is not the same. Mineral admixtures can improve the performance of some aspects of concrete, but also affect the performance of other aspects. For example, silica fume can improve the strength and durability of concrete, but the need for silica fume If the amount of water is large, the dosage is limited, and the self-drying shrinkage of concrete mixed with silica fume will also increase; the water demand of mineral powder is not large, and the early strength of concrete mixed with mineral powder is slightly lower, and the self-drying shrinkage increases; The self-drying shrinkage of fly ash concrete is small, and the use of high-quality fly ash can reduce the water demand of concrete to a certain extent, but the carbonation resistance of fly ash concrete will decrease to a certain extent, etc.

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