Errors in cement production
Date：2019-11-13 17:37 Source：未知Views:
The following errors in cement plants may affect the quality of concrete.
Mistake 1: ignore the cement factory temperature, think that the quality and control of concrete will not have an impact
Cement temperature is too high, adverse consequences have several aspects: first, it is possible to cause gypsum dehydration (generally think that the water will lose crystallization when more than 135℃ dihydrate gypsum, into half water gypsum);Second, high temperature cement hydration speed;Third, too high temperature will have an impact on water consumption and intensity;Fourth, the poor adaptability of admixture is caused.Before two kinds of circumstances, the main can cause a false coagulation or quick-setting cement, and then two situations is also interconnected, the higher the temperature will lead to water consumption increase sharply, the late strength drops, will naturally cause the water reducing admixture components cannot be in the process of cement hydration quickly improve the working performance of concrete, improve liquidity and, sometimes even several times more dosage of admixture also of no help.
Mistake area two: one-sided pursuit cement fineness
Cement fineness is a controversial issue.In order to maximize the potential of clinker, many cement production enterprises pay too much attention to fineness.Generally speaking, the finer the cement, the more fine particles, the faster the cement hydration rate, the more conducive to the development of strength.However, from the point of view of concrete, the finer the cement, the larger the water demand, the poor adaptability of the admixture, the greater the hydration heat, the greater the possibility of cracking.The results showed that the particles of 3 ~ 30 micron in cement had a main effect on the strength growth, while those of more than 60 micron had no effect on the strength, but could stabilize the volume.For particles less than 10 mu m, they mainly have an effect on early strength and require a large amount of water, while for particles less than 3 mu m, they only have an effect on early strength and require a larger amount of water.
Misunderstanding three: one-sided pursuit of cement strength, favoring fast setting
It is generally believed that high strength grade cement will be better than low strength grade cement.And early strength type R cement will definitely be better than ordinary cement.In order to achieve higher strength grade cement, the general cement plant will increase C3S content, increase fineness to meet the requirements, and achieve rapid setting is no more than to improve the content of C3A.
Mistake four: cement grinding aid add to have nothing to do with commercial concrete enterprise
In order to improve the output of cement bench, many cement production enterprises tend to use grinding AIDS to increase production and reduce consumption. The addition of grinding AIDS brings changes in cement quality and also leads to fluctuations in concrete performance. Especially, the.change in working performance increases the cost of commercial concrete enterprises.The results show that the cement prepared by adding grinding aid is related to the bad adaptability of water reducer.The addition of grinding AIDS cut off the effective contact between C3A and gypsum and increased the reactivity of cement single mineral, especially the reactivity of C3A, so that C3A and gypsum could not achieve the best match.