HPMC对PC-CSA复合浆体流变性的影响及机理分析

Effect of HPMC on Rheological Properties of PC-CSA Composite Pastes and Its Mechanism Analysis

关键词:  硅酸盐水泥  硫铝酸盐水泥  羟丙基甲基纤维素  流变性  机理分析

Key words:  Portland cement  calcium sulfoaluminate cement  hydroxypropyl methylcellulose  rheological property  mechanism analysis

摘要:

研究了高低黏度羟丙基甲基纤维素（HPMC）对硅酸盐水泥（PC）-硫铝酸盐水泥（CSA）复合浆体流变性的影响及其机理.结果表明：HPMC在水泥颗粒表面的吸附及其对孔溶液动力黏度的提高阻碍了颗粒的迁移，进而增加了复合浆体的初始表观黏度；HPMC掺量越大，初始表观黏度越高，且高黏度HPMC改性浆体的初始表观黏度比低黏度HPMC改性浆体更高；随着时间的推移，HPMC逐渐吸水膨胀，导致其改性浆体的表观黏度也逐渐增大；HPMC的吸水效果受孔溶液性质的影响，低黏度、低掺量HPMC改性浆体孔溶液的动力黏度较小，溶液在孔隙中的传输阻力也较小，HPMC更容易吸水；高黏度、高掺量HPMC改性浆体孔溶液的动力黏度较大，溶液在孔隙中的传输阻力也随之增大，从而阻碍了HPMC的吸水.

Abstract:

The effect and its mechanism of high and low viscosity hydroxypropyl methylcellulose（HPMC） on the rheological properties of Portland cement（PC）-calcium sulfoaluminate cement（CSA） composite pastes were investigated. The results indicate that the adsorption of HPMC on the surface of cement particles and its enhancement in the dynamic viscosity of the pore solution hinder particle migration， thereby increasing the initial apparent viscosity of the composite pastes. The higher the dosage of HPMC， the higher the initial apparent viscosity. The initial apparent viscosity of the composite paste modified with high viscosity HPMC is even higher than that of low viscosity HPMC. Over time， HPMC gradually absorbs water and swells， resulting in a gradual increase in the apparent viscosity of the modified pastes. The water absorption capacity of HPMC is affected by the properties of the pore solution. For low viscosity and low dosage HPMC-modified paste， the dynamic viscosity of the pore solution is low， resulting in smaller transport resistance to solution within the pores， making it easier for HPMC to absorb water. However， the dynamic viscosity of the pore solution in a high viscosity and high dosage HPMC-modified paste is relatively high， leading to increased trasport resistance to solution within the pores， which hinders the water absorption of HPMC.