The Influence Of Admixture On The Performance Of Self Compacting Concrete

Based on the problems existing in the research and application of energy-saving waste and self compacting concrete,this paper selects fly ash and slag powder as the admixture of self compacting concrete to study the influence of different dosage,different grade and different mixing form on the performance of self compacting concrete.The researche of the paper begins to adopt the absolute volume method in JG/T 283-2012,and references CECS 203-2006 and JGJ/T 283-2012 to calculate the standard mix proportion of self compacting concrete.After trial mix and adjustment,the standard mix proportion of C40 self compacting concrete is obtained.On that basis,the paper study the effect of fly ash and slag powder on workability,strength and dry shrinkage property of self compacting concrete by change the quality grade,proportion and blending form of fly ash and slag powder.And the hydration products of self compacting concrete were analyzed by X-ray diffraction.To sum,the paper use the computer comparative analysis program to comprehensively compare the influence of single or compound admixtures on the performance of self compacting concrete,and btain the results that the mix proportion which has better influence on the performance of self compacting concrete and higher economic benefit,which provides theoretical and experimental basis for the application of self compacting concrete in actual construction.The test results show that the change of quality grade and content of fly ash and slag powder will affect the workability,strength and dry shrinkage of self compacting concrete.The filling ability and gap passing ability of self compacting concrete improve with the increase of fly ash and slag powder,due to the poor activity of class III fly ash,the workability of self compacting concrete is basically not improved.Under the condition of 30%proportion,the age strength of self compacting concrete reduces with the decrease of the quality grade of fly ash and slag powder.The strength of self compacting concrete decreases with the increase of the content of fly ash of grade II or slag powder of grade S95.When the total amount of fly ash and slag powder is 30%,the different proportion of fly ash and slag powder has little effect on the filling and gap passing of self compacting concrete.However,when the total amount of composite admixture is 40%,the filling ability of self compacting concrete will be slightly reducedand the gap trafficability will be significantly reduced with the increase of the proportion of fly ash.No matter 30% or 40% of the total amount of the admixture,the strength of the self compacting concrete decreases with the increase of the proportion of fly ash;The dry shrinkage of self compacting concrete can be effectively inhibited by the addition of grade II fly ash and S95 slag powder.Through the comprehensive comparative analysis of the cost of cementitious materials and performance for self compacting concrete with different fly ash and slag powder contents and forms,it can be concluded that:Adding 10% S95 slag powder,10% class II fly ash,20% S95 slag powder,20% class II fly ash and 10% S95 slag powder into the self compacting concrete has a good effect on its comprehensive performance and has a high economic benefit.