磷石膏基水泥的早期水化性能研究

Early hydration properties of phosphogypsum-based cement

研究了原样磷石膏、200℃煅烧磷石膏、800℃煅烧磷石膏制备的磷石膏水泥的力学性能(对应编号分别为:MPC-1、MPC-2和MPC-3),进行了不同改性磷石膏基水泥早期水化放热速率及28 d水化产物的测试分析。结果表明:煅烧磷石膏尤其高温煅烧磷石膏可发挥更好的硫酸盐激发效果,有效提高磷石膏基水泥的强度,尤其是早期强度。800℃煅烧磷石膏水泥MPC-3试样3、28d强度分别为20.1、44.7 MPa,达到42.5R水泥强度等级要求;煅烧磷石膏基水泥的早期水化进程明显加快,相对MPC-1试样,MPC-2、MPC-3第二放热峰出现时间分别提前约10 h和17 h;磷石膏基水泥的水化产物主要为钙矾石和C-S-H凝胶,高温煅烧磷石膏基水泥水化产物更为密集。

Influence of phosphogypsum,200 ℃ calcined phosphogypsum and 800 ℃ calcined phosphogypsum on paste strength of modified phosphogypsum-based cement（No.：MPC-1 MPC-2 and MPC-3） were tested;Furthermore,early hydration exothermic rate and 28 d hydration products were systematically compared.Results showed that calcined phosphogypsum ,especially high temperature calcined phosphogypsum can play better stimulate sulfate effect,effectively improve strength of MPC,especially early strength.800 ℃ calcined phosphogypsum-based cement with the compressive strength 20.1 MPa at 3 d and 44.7 MPa at 28 d can meet the standard of Portland cement of 42.5R grade in strengths.Early hydration process of MPC accelerated markedly ,the second exothermic peak of MPC-2 and MPC-3 can respectively advance for 10 h and 17 h relative to MPC-1.Hydration products of phosphogypsum-based cement were mainly ettringite and C-S-H gel,which were more intensive for MPC-2 and MPC-3.