Research On Influence Of Additives About Properties Of Dry-mixed Mortar

Dry mixed mortar is a very important building material in civil engineering industry.Admixture is a kind of indispensable ingredient to dry mixed mortar.In this paper,the influence of different additives on dry mixed mortar of fly ash and limestone powder mortar is studied by comparison.The optimum proportion of four admixtures including redispersible latex powder,cellulose ether,starch ether,water reducing agent applied in three kinds of mortar was studied by orthogonal test.The performance of mortar is improved by adding different proportion of single admixture.The studies show that:The fly ash mortar using Aotelong’s additives needs less water and the apparent density is only 1819.5kg/m~3.This mortar with the lowest bond strength has poor water retention effect and the loss of 2h consistency is more than 20%.The mortar with Qigong-admixturehastheworstcompressioneffect.Themortarwith Zhoukou-admixture has very excellent 2h-consistency loss rate.With the Yushun-admixture of mortar compressive and tensile strength of mortar has good effect than other motar.In limestone powder mortar,The ratio of water to material can reach 14.3%when Fangdakang-admixture mortar that owns the highest moisture content achieves the same consistency.The Aotelong-admixture motar’s strength test is worse than the others.The mortar with Qigong-admixture has a great influence on the loss of 2h-consistency.The Yushun-admixture motar has the maximum apparent density and the minimum gas content.Most important of all,the late strength increases surpass other mortars and the tensile bond strength is the highest in all mortars.The optimum ratio of four kinds of additives is calculated by orthogonal test in M5-mortar.When the proportion of additives is 0.72‰,the water retention effect and strength value are higher,and the later strength can reach 12.03MPa.The optimum dosage of mortar is 0.65‰in M10-mortar and water retention rate mortar is 97.34%.The amount of admixture in plastering mortar is 0.7‰.When the amount of admixture in masonry mortar is 0.64‰and in plastering mortar is 0.7‰,the water retention rate is more than 95%.In addition,the maximum strength can reach 23.90MPa.