LIU Fengli¹，ZHANG Ankang¹，LIU Junhua²，WANG Tian¹

(1.Laboratory for Recycled and Functional Building Materials, Henan University, Kaifeng 475004, China;2.School of Civil Engineering and Architecture, Kaifeng University, Kaifeng 475004, China)

Abstract：In order to improve the low strength of desulfurized gypsum based cementitious material and realize the high-value utilization of desulfurized gypsum, based on response surface method, the optimization of modified desulfurized gypsum composite system was designed.Modified desulfurized gypsum cementitious system was prepared by using quicklime-fly ash-cement as modifier, partially replacing desulfurized building gypsum, the effects of different modifiers and their interactions on the 1 d and 28 d compressive strength of the composite cementitious materials were studied.The predictive pattern of response surface was established, and checked by trial.The outcomes indicate that when the mass ratio of different modifiers is 5.53% of quicklime, 9.17% of fly ash and 15.32% of cement, the performance of the composite is the best.Under this ratio, the 1 d and 28 d compressive strength of the composite are 5.50 MPa and 20.30 MPa respectively, which is 48.65% and 67.77% higher than the pure desulfurized gypsum system.The error of practical and predicted value is only 0.90% and 0.74%, which shows that the forecast of response surface method is exact, and the way is practicable.

Keywords：desulfurized gypsum; response surface methodology; compressive strength; optimal proportion

Received：2022-09-22，Revised：2022-10-27,Online：2023-01-11 08:49。

Funding Project：河南省科技攻关项目，编号：212102310565；河南省高等学校重点科研项目，编号：21B560008；固废资源化利用与节能建材国家重点实验室开放基金资助项目，编号：SWR-2020-007。

First Author：刘凤利(1978—)，女，副教授，博士，硕士生导师，研究方向为绿色、节能建筑材料。E-mail：lfl@henu.edu.cn。