Mix Proportion Design Method And Interactive Design Program Of Alkali-Activated Slag Concrete Based On Key Parameters

Alkali-activated slag concrete has attracted the attention of many researchers because of its characteristics and properties similar to Portland cement concrete and its advantages of high strength,high durability and environmental protection.Although alkali-activated slag concrete has many advantages,due to the lack of specific application standards,especially the lack of mix proportion design and application specifications like ordinary concrete,it still needs a lot of research on the practical engineering popularization and application.In this paper,slag is used as cementitious material,a mixed solution of water glass and sodium hydroxide is used as activator to activate the slag,the alkali-activated slag concrete specimens were preparation.Based on the analysis of the key parameters influencing the mechanical properties of alkali-activated slag concrete,a design method of mix proportion of alkali-activated slag concrete was proposed,and an interactive program of mix proportion based on this method was developed The main contents and results of this paper are as follows:(1)The key parameters affecting the mechanical properties of alkali-activated slag concrete were studied by orthogonal test,including slag dosage,alkali-binder ratio,alkali equivalent and water glass modulus,and the optimal ratio within the given factors and levels.The results show that the most important factor affecting the mechanical properties of alkali-activated slag concrete is alkali equivalent,followed by water glass modulus,and finally alkali-binder ratio and slag dosage.Alkali equivalent has a great influence on the 28d compressive strength of concrete,while the amount of slag has little effect on the 28d compressive strength of concrete.Taking the 28d compressive strength of alkali-activated slag concrete as the index,when the alkali equivalent is 13%,the water glass modulus is 1.8,the alkali-binder ratio is 0.48,and the slag dosage is 350kg/m~3,the mix proportion is optimal.(2)A design method for determining the mix proportion of alkali-activated slag concrete based on the selection and calculation of key parameters is developed.The main process includes:calculating the preparation strength of alkali-activated slag concrete by using the preparation strength formula;the modulus of water glass was determined according to the preparation strength and final setting time.The alkali equivalent was determined according to the preparation strength and water glass modulus.The alkali-binder ratio formula was obtained by linear regression analysis.The amount of alkali solution was determined according to the consistency of viber;the amount of slag was calculated according to the alkali-binder ratio and alkali solution.Determine the sand rate by test method or empirical method or look-up table method;the amount of coarse aggregate and fine aggregate was calculated according to the mass method.(3)An interactive program for designing and calculating the mix proportion of alkali activated slag concrete was developed by EXCEL.The program for determining the strength of preparation,the modulus of sodium silicate and the dosage of alkali solution was designed by using IF condition function,and the program for determining the equivalent of alkali was designed by using SUM function.