P·O42.5 cement,fly ash,limestone superfine powder,mineral powder and admixtures were used as raw materials to prepare cementitious mortar.The orthogonal test was used to determine the optimum ratio of cement-based cementitious materials,and the effects of starch ether on cellulose ether substitution rate and expansion agent on the performance of cementitious mortar were investigated,the hydration products and microscopic morphology were analyzed by XRD and SEM respectively,and the mecha-nism of action of additives was studied.The results showed that the performance of cement-based cementitious materials was opti-mal when the mass ratio of cement,fly ash,mineral powder and limestone ultrafine powder was 22:4:4:5;the appropriate amount of starch ether instead of cellulose ether could enhance the water retention of mortar,increase the strength of mortar and improve the shrinkage;a small amount of expansive agent could improve the early strength of mortar,and an increased amount of admixture could reduce the early strength and improve the later strength of mortar.The finally prepared cement-based bonded mortar meet the requirements of JC/T 890-2017"Special Mortar for Autoclaved Aerated Concrete Wall".
维普
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