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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2021, Vol. 40 ›› Issue (2): 565-572.

Special Issue: 资源综合利用

• Solid Waste and Eco-Materials • Previous Articles     Next Articles

Performance Influence Mechanism of Lightweight Plastering Phosphorus Building Gypsum

WU Chao1, YANG Lin1, LI Wei2, WANG Jiacai3, CAO Jianxin1, LI Jianqiu3   

  1. 1. School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China;
    2. Guizhou Zhenghe Aerated Concrete Co., Ltd., Guiyang 550025, China;
    3. Guizhou Chuanheng Chemical Co., Ltd., Fuquan 550500, China
  • Received:2020-09-09 Revised:2020-11-06 Online:2021-02-15 Published:2021-03-10

Abstract: Light gypsum plaster was prepared by using phosphorus building gypsum (PBG), sodium citrate (SC), methyl cellulose (MC) and vitrified microsphere as raw materials. The influence mechanism of admixtures and lightweight aggregates on mortar properties was systematically analyzed. The results show that sodium citrate improves the fluidity of mortar, and the compressive strength of the sample reaches 16.3 MPa when the content of sodium citrate is 0.8% (all the content are mass fraction). However, the fluidity of the mortar is reduced by methylcellulose, and the compressive strength of the sample is only 11.3 MPa when the content is 0.40%. The density of the mortar added with vitrified microsphere decreases, and the fluidity and setting time of the mortar also decrease. The water retention rate and tensile adhesive strength of hardened body increase. When 95% phosphorus building gypsum, 5.0% vitrified misrosphere are used and 1.0%SC and 0.20%MC are added by according to the quality of PBG, the properties of the mortar samples can meet the requirements of lightweight plaster gypsum properties in GB/T 28627—2012 “gypsum plaster”. With the increase of SC content, the morphology of dihydrate gypsum, which is the hydration product of lightweight plastering gypsum, changes to long strip and needle shape. The crystal crystallinity decreases and the overlapping degree increases, which makes the flexural strength increase, the compressive strength and tensile adhesive strength decrease. With the increase of MC content, the morphology of dihydrate gypsum, which is the hydration product of lightweight plastering gypsum, becomes thick plate, the degree of overlapping between crystals and crystallinity increases, which makes the hardening strength increase.

Key words: lightweight plaster gypsum, phosphorus building gypsum, mechanical strength, crystal morphology, influencing mechanism

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