羧甲基淀粉对地质聚合物性能及结构的影响

The effect of carboxymethyl starch on properties and structure of geopolymer

由于地质聚合物的高碱性,目前市面上使用的水泥基增稠剂并不适用地质聚合物体系。为了研发一种适合地质聚合物的增稠剂,采用水溶性羧甲基淀粉作为原料,结合地质聚合物反应机理,研究了其对新拌地质聚合物浆体流变行为的影响,并对改性后地质聚合物的固化性能进行了跟踪研究。实验结果表明:羧甲基淀粉能显著提高地质聚合物浆料的内聚力,有效增强其触变性、屈服应力和塑性粘度;羧甲基淀粉具有保水和缓凝作用,能有效改善地质聚合物的干燥收缩;尽管羧甲基淀粉降低了早期抗压强度,但28 d抗压强度并无明显变化。实验的结果说明了羧甲基淀粉与地质聚合物有较好的兼容性,有望成为一种绿色环保的外加剂。

Because of the high alkalinity of geopolymer,the current commercial cement-based thickener is not suitable for geopolymer system,which has motivated us to develop an alternative thickener suitable for geopolymers.Based on the reaction mechanism of geopolymers,we used water-soluble carboxymethyl starch(CMS)as raw material,studied its influence on the rheological behavior of fresh geopolymer slurry,and tracked the curing properties of modified geopolymers.The results show that:(1)CMS can significantly improve the cohesion of geopolymer slurry and enhance its thixotropy,yield stress and plastic viscosity;(2)CMS possesses water retention and retarding effect for geopolymer,which can effectively reduce the drying shrinkage of geopolymer;(3)Although CMS reduces the early compressive strength,the 28d compressive strength does not change significantly.The experimental results demonstrate that CMS has a good compatibility with geopolymer,and it is expected to be used as a green admixture.