| Using ground granulated blast furnace slag powder(GGBS)and fly ash(FA)to prepare inorganic cementitious materials to replace ordinary portland cement has excellent environmental and considerable economic benefits.At the same time,they can work together effectively.They have good mechanical and working properties under the appropriate ratio design.In this paper,based on the two aspects of fluidity and unconfined compressive strength,the working and mechanical properties of the materials are optimized at the same time,the proportion and composition design of alkali activated GGBS / FA inorganic cementitious materials is carried out,the hydration products and mechanism of composite cementitious materials are studied,and the relationship between curing strength and micro-mechanism of cementitious material is analyzed.Different erosion curing environments are specially designed to explore the effects of chloride,sulfate and seawater on the alkali activated GGBS / FA inorganic cementitious materials,so as to summarize the general laws with universality and objectivity and guide the design of alkali activated GGBS / FA inorganic cementitious materials in practical production and application.The main research contents and relevant conclusions are as follows:(1)In order to harden the slurry with good mechanical properties and working properties at the same time,the best material ratio is determined from four aspects: the relative content of GGBS / FA,the type of alkali activator,the content of alkali activator and the water-solid ratio.The alkali activated GGBS / FA inorganic cementitious material has the best performance when the relative content of GGBS /FA is 80:20,the alkali activator adopts 2% Na OH,and the water-solid ratio is 0.37,and the compressive strength can reach 49.9Mpa.(2)The sample G80SH20 was characterized by XRD,FTIR and SEM 37 hydration products and mechanism.The development trend of age intensity was studied.The age intensity curve was fitted by function fitting method,and the best fitting function curve was obtained.(3)The changes of mechanical properties,hydration mechanism and micro mechanism of alkali activated GGBS/FA material under three different aggressive environments: chloride solution,sulfate solution and artificial seawater were studied.This paper mainly discusses the evolution law of hydrotalcite like phase and other hydration products in alkali activated GGBS/FA materials with the change of solution environment,and preliminarily establishes the possible relationship between the mechanical properties of the materials and hydration mechanism and micro mechanism. |
