Experimental Study On Mechanical Properties And Environmental Adaptability Of Silica Fume Lightweight Aggregate Concrete

This article selects pumice as coarse aggregate and replaces cement with quality such as silica fume for concrete preparation.Combined with seasonal environmental impacts in Inner Mongolia,mechanical properties tests were performed on light-weight aggregate concrete with different amounts of silica fume,and the relationship between macro mechanics and micro properties was analyzed by scanning electron microscopy,stomatal structure analysis,and nuclear magnetic resonance tests.Two kinds of combined working conditions,sulfate-dry-wet cycle and sulfate-freeze-thaw cycle,were designed to study the environmental adaptability of silica fume lightweight aggregate concrete.The following research results were obtained through experimental analysis:(1)In terms of mechanical properties,the appropriate amount of silicon powder can increase the compressive strength of lightweight aggregate concrete.When the amount of silicon powder is 6%,the compressive strength is the best;combined with microscopic analysis,it is found that an appropriate amount of silicon powder It can improve the pore structure of lightweight aggregate concrete.The best effect is achieved when the content is 6%,so that the porosity reaches a minimum.(2)During the sulfate-dry-wet cycle test,the relative dynamic elastic modulus,mass loss rate,and corrosion resistance are used as test indicators.The results show that the addition of an appropriate amount of silica fume can improve the dry and wet resistance of lightweight aggregate concrete during salt invasion.(3)Under sulfate-dry and wet cycle conditions,the compressive strength and nuclear magnetic resonance tests are combined with the grey entropy correlation to analyze the effect of pore characteristic parameters on the compressive strength,and the irreducible fluid saturation,The ratio of pore radius from 0 to 0.1 ?m is the comparison column,and the compressive strength is the reference column.GM(1,3)prediction model is established.(4)Under the conditions of sulfate-freeze-thaw cycle,analyze the law of mass loss rate and relative dynamic elastic modulus.The damage degree was defined based on the dynamic elastic modulus,and a freeze-thaw damage model of light-weight aggregate concrete was established.