Study on the properties and application of magnesium anticracking agent regulated by hydration heat
The effects of the hydration heat regulated magnesium anti-cracking agent(TM)on the hydration heat,expansion properties,mechanical properties and drying shrinkage properties of the cement paste were studied,and its action mechanism was explored by XRD and SEM.The data showed that the injection temperature has a significant impact on the temperature suppres-sion effect of TM.When the injection temperature is 20℃,the temperature inhibition rate of cement paste gradually increases to 42.6%.When the injection temperature is increased to 35℃,the difference of the content on the temperature inhibition effect is not significant,but the setting time of cement is prolonged.With the increase of curing temperature,the hydration reaction of TM will increase rapidly,and the expansion period will decrease significantly.TM can reduce the drying shrinkage of concrete.When curing to 120 d,the shrinkage rate can be reduced by 19.1%compared with the blank group.With the increase of TM content,the compressive strength of concrete specimens at early stage(3 d)will decrease significantly,but the mechanical properties of con-crete specimens at long age(60 d)will not be affected.The change of cement hydration process,hydration product formation and microstructure compactness by TM is the fundamental reason for improving the crack resistance of concrete.With addition of 6%TM,the temperature rise of the test section of concrete engineering structure is reduced by 4.8℃,the shrinkage value is reduced by 131.3 micro-strain,and the number of cracks is only 1.
万方数据
维普
