Properties and reaction mechanism of magnesium phosphate cement modified by calcium lactate: Fid-Bau Portal

Properties and reaction mechanism of magnesium phosphate cement modified by calcium lactate

Li, Yue / Wang, Qiuao / Sun, Jia / Lin, Hui / Luo, Xiao

Abstract The properties of magnesium phosphate cement (MPC) are studied by measurements of setting time, flowability, compressive strength and by multiple technique analyses of pH values, calorimetry, XRD, TG, MIP and SEM taking calcium lactate (CL) content as variables. Results show that CL can significantly prolong the setting time and promote the synergetic development of compressive strength of MPC, but the addition of CL leads to a decrease in flowability of MPC. Comprehensive consideration on these properties, the optimal dosage of CL is 5%. In this case, the setting time, flowability and 1 day & 28 days compressive strength of MPC are 84 minutes, 185 mm, 40.8 MPa & 54.2 MPa, respectively. Multiple technique analyses show that the addition of CL can decrease the liquid phase pH value and hydration rate of MPC, resulting in the extension of setting time. A low content of CL (3%) can improve the reaction degree and optimize the matrix pore structure of MPC, and thus promoting the strength development (50.90 MPa increased to 65.93 MPa). However, an excessive addition of CL (7%) will lead to the decrease in reaction products and the increase in matrix porosity of MPC, resulting in a decrease in compressive strength (43.30 MPa reduced to 37.36 MPa).

Highlights • Calcium lactate can prolong the setting time and promote the synergetic development of compressive strength of MPC. • The effect of the calcium lactate on setting time, flowability and compressive strength of MPC is presented. • The reaction mechanism of calcium lactate on MPC is analyzed. • The effect of calcium lactate on the hydration products and microstructure of MPC is analyzed.