Early strength agent for pavement concrete

Abstract

The invention relates to an early strength agent for pavement concrete. Reference cement of concrete is taken as a substrate. The early strength agent is prepared from the following raw materials in parts by weight: 1.5 to 2.5 parts of sodium sulfate, 1.6 to 2.5 parts of gypsum, 0.01 to 0.07 part of triethanolamine and 0.8 to 1.3 parts of sodium chloride. Organic matters and inorganic salts are compounded to form the early strength agent; four components: sodium sulfate, gypsum, triethanolamine and sodium chloride are compounded and used, the compressive strength of the obtained precast concrete at each age is higher than that of concrete that does not contain the early strength agent, the early cement strength can be enhanced, the later strength is not influenced, and the cement setting time, stability and fluidity are not influenced.

Description

technical field [0001] The invention belongs to the technical field of concrete admixtures, in particular to an accelerator for pavement concrete. Background technique [0002] Generally speaking, concrete engineering accounts for about half of the entire civil engineering, so the hardening speed of concrete plays a very important role in shortening the construction period of civil engineering. At present, there are many external admixtures used in China to improve the early strength of concrete at 10-40°C, such as cement-water glass slurry early strength agent, which has the advantages of short setting time and high setting rate. Over the years, concrete early strength agents have been widely used in soft soil reinforcement, well wall grouting, water seepage accident treatment, etc., and solved many key problems. [0003] The curing of concrete mix is ​​mainly maintained by the reaction of silicate in sodium silicate and Ca2+ produced by cement hydration to form C-S-H gel....

AI Technical Summary

Problems solved by technology

[0003] The curing of concrete mix is ​​mainly maintained by the reaction of silicate in sodium silicate and Ca2+ produced by cement hydration to form C-S-H gel. Therefore, cement-water glass slurry has the problems of low low-temperature strength and poor durability of stone bodies. In a low temperature environment of approximately 4°C, the hydration reaction of ordinary cement almost stops, and the silicate in sodium silicate reacts with Ca2+ to form a serious shortage of C-S-H gel, which leads to low low-temperature strength of concrete. At the same time, the calcium content in cement is fixed. Yes, the amount of calcium hydroxide generated by its hydration and the reaction between sodium silicate and calcium hydroxide is also certain. Too much sodium silicate is not beneficial to the strength of the stone body, but may reduce the strength of the system. This is because C-S-H coagulation The gel needs high alkalinity to maintain its stable existence, and the dissolution of NaOH will cause the decomposition of the C-S-H gel, resulting in the destruction of the structure

When the concrete material is under low-temperature dry conditions, the silica gel will be dehydrated, and the volume of the stone body will shrink and produce cracks, resulting in the pulverization of the stone body and failing to form effective strength.

Images