Effects Of Basaltic Volcanic Powder On Cement Concrete Performance Study

Our country is abundant in basaltic volcanic rocks resources.Therefore,to develop the application of basaltic volcanic rocks in cement and concrete is significant for the utilization of the basaltic volcanic rocks as well as environmental protection,which is meaningful to the society and the economics.The article studies the chemical and physical properties of basaltic volcanic powder,such as its chemical composition,mineral composition,particle size and others by using methods of XRD,XRF,DSC etc.;it investigates the influence of basaltic volcanic powder on the cement hydration process when mixed with the cement;and by studying the regularity of the basaltic volcanic powder with different fineness and proportion affecting the mechanical performance of different strength grade concrete?C30,C40 and C50?,we get the optimal mixture ratios of C30,C40 and C50 concrete;it is also studied that the effect of the basaltic volcanic powder mixed with concrete on the resistance performance of dry shrinkage,seawater invasion and tidal invasion of the concrete;it also analyzes the morphology of basaltic volcanic powder in cement concrete by SEM and discusses its reaction mechanism.Through the above research,this thesis obtains the following findings and conclusions.?1?Micro powder particles,mostly irregular flaky and plate,are grinned from basaltic volcanic rocks and the chemical composition is SiO₂?Al₂O₃?Fe₂O₃ and CaO.The main mineral composition is anorthite,andesine,anemousite and albite.The surface area of micro powder particles is 419.65 m²/kg?432.79m²/kg?484.57 m²/kg respectively.Mixing he basaltic volcanic powder whose specific surface area is 432.79 m²/kg,slag powder and fly ash according to equal proportion,the curve which is much closer to the Fuller packed distribution curve can be acquired.?2?Ca?OH?₂ can be reacted with basaltic volcanic powder to get alkaline hydrated product.And the greater the fineness of the powder,the greater the activity,and much more Ca?OH?₂ can be consumed.The compressive activity index of the basaltic volcanic powder with a specific surface area of 484.57 m2/kg,432.79 m2/kg and 419.65m2/kg decreases in turn.The compressive activity index of the basaltic volcanic powder with 484.57 m²/kg is71.7%,which is higher than the fly ash?67.1%?.By analyzing the compressive strength and rupture strength,the content of the basaltic volcanic powder in concrete should be less than30wt%.?3?With the increasing dosage of basaltic volcanic powder,the compressive strength of the concrete of each strength grade is reduced.However,when the dosage proportion of basaltic volcanic powder is 20 wt%,appropriate fineness basaltic volcanic powder concrete has a higher strength than fly ash concrete in different strength grade concrete mix ratio.?4?Used basaltic volcanic powder with a specific surface area of 484.57 m²/kg as the main raw material,the optimal dosage proportion of basaltic volcanic powder,superplasticizers and sand coarse aggregate ratio are determined in following strength grade concrete:In C30 concrete,the optimal dosage proportion of basaltic volcanic powder is 12 wt%;superplasticizers and sand coarse aggregate ratio is 2 wt%,47 wt%.In C40 concrete,the optimal dosage proportion of basaltic volcanic powder is 9 wt%;superplasticizers and sand coarse aggregate ratio is 1.9 wt%,43 wt%.In C50 concrete,the optimal dosage proportion of basaltic volcanic powder is 9 wt%;superplasticizers and sand coarse aggregate ratio is 2.2 wt%,38 wt%.?5?The basaltic volcanic powder concrete has a better resistance to dry shrinkage,resistant capability under seawater and tidal zone performance than fly ash concrete.?6?Basaltic volcanic powder can take part in the hydration reaction of cement,and the well-grained-size distribution fills the holes inside the concrete to reduce the porosity.Thus the microstructure of concrete is more compact,and the compressive strength and durability of basaltic volcanic powder concrete is improved.