Preparation and performance study of phosphate geopolymers

LIU Tengfei; XIE Xiaoli; ZHOU Yusheng; GAO Jian; ZHENG Yu

doi:10.3969/j.issn.1001-702X.2023.12.002

Abstract：In this paper,the effect of the three factors,including water-cement ratio,Si/P and P/Al,on the flowability,setting time and compressive strength of geopolymer were investigated by using an orthogonal test.The test results showed that Si/P had the greatest influence on setting time and flowability.with the increase of Si/P,the setting time was gradually shortened and flowa-bility decreased.When Si/P is 6,the minimum time of initial setting and final setting were 4.7 h and 6.9 h,respectively,and the maximum value of flowability was 299 mm.The water-cement ratio and Si/P are the most important factors affecting the compres-sive strength,which decreases with the increase of water-cement ratio and Si/P at different ages.P/Al has no significant effect on the compressive strength of geopolymers,but the workability of geopolymers decreases significantly with increasing P/Al.In addition,the compressive strength gradually increased with the increased age.When the water-cement ratio was 0.50,the compressive strength of geopolymer at 3,7,14 and 28 days were 13.94,16.26,19.37 and 19.92 MPa,respectively;when the Si/P was 4,the com-pressive strengths of geopolymer at 3,7,14 and 28 days were 9.37,16.36,19.19 and 20.44 MPa.When water-cement ratio is 0.50,Si/P is 4 and P/Al is 3.2,phosphate geopolymer has the optimum properties.