Titanium Gypsum Strength Transition Point Model Establishment and Strength Mechanism Analysis

Studying various performance characteristics of titanium gypsum is of great significance for the recovery,resource utilization and re-use of titanium gypsum.In order to maximize the use of titanium gypsum,experiments were performed by replacing part of titanium gypsum with flue gas desulfurization gypsum（FGD）,and moisture content and strength tests were performed on titanium gypsum test blocks at different time points.The experimental results show that under natural curing conditions,with increase of the curing time both of the flexural strength and compressive strength of the titanium gypsum test blocks first decrease and then increase,and the moisture content decreases rapidly and then slowly.Using the Origin software to fit and analyze the experimental data,the Cubic（x,A,B,C,D） model can be used to predict the change in flexural strength and compressive strength of the titanium gypsum test block,and the LangmuirEXT2 function model can better predict the changes in moisture content of gypsum test blocks.The main reason for the decrease followed by increase in strength of titanium gypsum test blocks combined with SEM analysis is that the rapid loss of free water under natural curing conditions with the free water content around the dihydrate gypsum crystals decreased,and most of the water changes from physical adsorption to chemical adsorption which constitutes dihydrate gypsum crystals and forms effective structural strength.