The Preparation And Experimental Research At High Temperature Of Mechnical Properties Of Magnesium Phosphate Cement Concrete

Magnesium phosphate cement(MPC) is a new kind of binder which can provide many essential requirements for rapid repair applications,such as quick setting, development of high early strength, high bonding strength and good durability. Based to the merit of the MPC, the preparation and mechanical behavior of MPC concrete which is made from MPC will be investigated in this thesis.MPC concrete behavior under high temperature is very complex, and it's mechanical behavior changes along with the variation of the temperature. Therefore, the variation of MPC concrete behavior after being heated to temperature up to 1000℃is investigated by experimental and theoretical analysis. The paper analyses the variation laws of compressive strength which responds to the changes of temperature. The loss of quality is analysed. Conductivity and specific seat of MPC concrete are measured through the experiment and the thermal field is simulated through finite element based ABAQUS software.1. It is found that the setting of MPC is greatly influenced by the reactivity of magnesium. The reactivity of magnesium influences the setting time of MPC paste and mortar. The paper chooses magnesium and proportion preferably which have suitable setting time and strength development to prepare MPC paste and mortar specimen.2. The test blocks are heated in an electric furnace. The Experiment analyses the variation of MPC paste,mortar and concrete mechanical properties with different temperature and ingredient. The experiment results show that compressive strength of MPC paste and mortar specimen after high temperature tend to degrade gradually as the temperature increases.The experiment also shows compressive strength of MPC concrete tend to degrade gradually in the same high temperature. The compressive strength of MPC concrete in high temperature is higher than that after high temperature.Meanwhile it gains the conclusion that the mass of MPC paste and mortar specimen after high temperature tend to gradually increase with rising temperature.The mass loss of MPC paste and mortar has major change before 600℃,and it changes smoothly when exceeds 600℃. The mass of MPC concrete specimen after high temperature tend to go updown with rising temperature.3. Conductivity and specific seat of MPC concrete are measured through the experiment and the thermal field is simulated through finite element based ABAQUS software. The paper attests the fact that MPC concrete after high temperature have hysteresis quality when the temperature rise.