Influence Mechanism of Hornblende Ballast Machanical Sand and Stone Powder Content on Properties of Concrete
In order to clarify the influence of stone powder on the performance of concrete in the process of sand making by hornblenede ballast waste slag,the hornblende ballast waste slags from six areas in Hebei province surrounding Beijing and Tianjin Region were taken as experimental materials.The influence mechanism of hornblende ballast mechanical sand and stone powder content on the workability,mechanical properties and microstructure of concrete were investigated by mechanical tests,slump test,zata potential test,SEM and FTIR.The results indicate that except for Xinxin in the six regions,hornblende ballast mechanical sand can enhance compressive strength in all other regions.Wherein,Chengde and Xiaoshixia regions have the superior strengthening effect on concrete.Compared with concrete prepared by natural sand,after curing of 7 d,the compressive strength of C30 concrete prepared by Chengde and Xiaoshixia aggregate increases by 20.51％and 11.11％,and after curing of 28 d,the compressive strength increases by 10.79％and 6.58％,respectively.For C50 concrete,the compressive strength increases by 15.14％and 12.57％after curing 7 d,and increases by 14.55％and 16.55％after curing of 28 d,respectively.The optimal stone powder content of Chengde,Xinxin,Jiheng and Xiaoshixia is 8％～15％of cementitious material,but only about 5％for stone powder of Pingshan.Among,the stone powder content replacing cementitious materials in Chengde and Xiaoshixia regions is the highest.The reason is that the particle size of stone powder in these two areas is small.SEM shows that the stone powder shows obvious erosion and damage morphology under alkaline conditions,and more cementitious products are formed at the aggregate interface,which improves the degree of cementation between aggregate particles.In addition,the appropriate of stone powder content has a certain filling effect on the coarser manufactured sand concrete in Fengning area,which can improve the mechanical properties of concrete.The results of FTIR and Zeta potential tests show that the hornblende ballast waste slag rock powder can adsorb the poly carboxylate superplasticizer and react to form ionic compounds.The polycarboxylate superplasticizer improves the stability of the stone powder,cement and polycarboxylate solution system.This study can provide a reference for the application of hornblende ballast mechanical sand in ordinary concrete and the proportion design of stone powder replacing different cementitious materials in concrete.
国家科技期刊平台
NSTL
万方数据
维普
