The Performance Influence Study Of The Limestone Powder In Manufactured Sand Dry-mixed Mortar

Manufactured sand dry-mixed mortar is a kind of building mortar that the production of professional manufacturer and is made by cementing materials,manufactured sand,admixture,admixture and other components according to the performance,according to certain proportion.It has many advantages such as stable quality,mechanized construction,green environmental protection,etc.With large scales of infrastructure construction in our country,traditional mineral admixtures such as fly ash,slag powder are scarce increasingly in some areas.Limestone powder has been applied in the industry gradually as new mineral admixtures of accessible,high quality and low price.Accordingly,it is a major measure for saving resources,protecting the environment that limestone powder will is applied to manufactured sand dry-mixed mortar,it has economic,social and environmental benefits specially.This paper uses the comparative research method,analyzing the performance of limestone powder that different replace rate amount instead of fly ash and specific surface area as admixtures on physical,mechanical and permeability in manufactured sand dry-mixed mortar.The studies show that:It is maximum for fluidity and water-retention of mortar when limestone powder that specific surface area is 800 m2/kg and amount instead of fly ash to replace rate is 60%,comparison a single mixing fly ash is increased by 15.5%and 1.4%;With the increase of the limestone powder replace rate and specific surface area,the setting time and performance density is shorten;It is larger for the early compression and flexural strength of mortar when limestone powder that specific surface area is more than 600 m2/kg and amount instead of fly ash to replace rate is 60%,meanwhile,for 14 d bond strength,limestone powder that specific surface area is 600m2/kg,800 m2/kg,1000 m2/kg increased by11.8%,19.6%,25.5% of that without limestone powder;Limestone powder is conducive to manufactured sand dry-mixed mortar impermeability improved.Therefore,the manufactured sand dry-mixed mortar will have good comprehensive performance if appropriate of limestone powder and fly ash mixed,and the mixed ratio of 6:4,namely limestone powder content is 18% of cement,12% of the cement dosage of fly ash;and specific surface area of the limestone powder is800 m2/kg.