Study And Fabrication On Stone-frame Eco-concrete

Cement-based materials such as concrete have become the most demanding artificial materials for human society,and the environmental pollution caused by its application has received attention from various countries.The global emission-reduction trend imposes restrictions on carbon emissions in the cement industry,but the method which to reduce concrete output is contrary to the general trend of China's development.Therefore,to develop the ecological concrete materials with high aggregate content and low-carbon emission is an effective way to improve the above problems without decreasing its service performance.In this paper,the stone-frame concrete(SFC)is prepared by combine selfcompacting concrete(SCC)and aggregate interlocking concrete,which aims to form the interlocking structure with aggregate in larger size.The volume fraction of coarse aggregate in concrete increases,and its service performance is improved.The mix proportions of grouting mortar is optimized with its mobility,strength and shrinkage ratio,and some service performance of stone-frame concrete(mechanical properties,volume stability and adiabatic temperature rise)are investigated.Its preparation process was innovated by aggregate-fill technology(AFSFC),the conclusions drawn are as follows:1.The optimized grouting mortar has the following characteristics: lowbleeding rate,high fluidity and low-liquidity loses.Its yield stress is 60.12/Pa,the plastic viscosity is 1.18/s,the expansion is 360/mm,and the bleeding rate is 0.75%.The mortar which blend 30% supplementary cementitious material has better mechanical properties than ordinary mortar,and its shrinkage rate is reduced by 25%.The width of the mortar-aggregate interface transition zone is reduced,and its ITZ strength is improved.2.The minimum value of SFC grouting mortar slump flow is 350 mm,the optimum sand-frame particle size ratio is 1:20.With this sand-frame particle size ratio,its shrinkage value is 28.4% lower than that of ordinary SCC,and the adiabatic temperature rise is decreased by 21.52%.3.The compactness of SFC is improved by using the aggregate-fill technology,and the defects occurrence frequency on the cross section is reduced.Under the same sand-frame particle size ratio(1:20),the frame filling rate of AFSFC is reduced 2% than the SFC with preset aggregate,but its mechanical properties is slightly improved.4.During the filling process,use some smaller size aggregate to replace the original size aggregate can promote frame filling volume from 45% to 52%,its strength is increased by 15%,and the adiabatic temperature rise is reduced by 17%.5.Extend the law obtained from the above research to larger size concrete—rock-filled concrete,the frame filling volume of aggregate-fill rock-filled concrete and preset rock-filled concrete are 54% and 51%,respectively.The rock-filled concrete which use aggregate-fill technology is denser in filling and has low strength dispersion.Based on the theory of aggregate interlocking,the service performance of stone frame concrete with different sand-frame particle size ratio,frame volume ratio and different preparation process have been studied.The results show that its service performance is enhanced than SCC(strength,shrinkage and adiabatic temperature rise),while its life cycle carbon emissions,raw material production energy consumption and pollutant emissions are improved.