Effect of mineral admixtures on expansion properties of MgO expansion agent and its mechanism
MgO expansion agent has good expansion stability,which matches with concrete shrinkage and can effectively inhibit the formation of concrete shrinkage cracks.The effect of mineral admixtures on the expansion properties of MgO expander and its mechanism were studied.By testing the compressive strength,flexural strength and limited expansion rate of 8％MgO expansion agent concrete with different proportions,the influence of mineral admixture on the performance of concrete was investigated.The experimental results show that with the increase of fly ash content,the compressive strength and flexural strength of concrete decrease,but the slag has no obvious effect on its strength.The expansion process of concrete curing in water can be divided into latent induction period,rapid expansion period,slow expansion period and stable period.The addition of mineral admixture reduces the expansion effect of MgO expansion agent,and the higher the dosage,the greater the effect,among which the fly ash is more significant.The expansion is caused by the filling of pores by the Mg(OH)2 crystals generated by the MgO reaction.The mineral admixtures reduce the expansion by reducing the degree of MgO reaction and increasing the porosity.The slag has higher activity and less obstacle to MgO reaction.
mineral admixturesMgO expansion agentpore structuremechanical property
万方数据
维普
