Strength Experiment and Mechanism Analysis of Cement Mortar with Sticky Rice Pulp

Cement mortar with sticky rice pulp is an innovative composite material. Investigating its mechanical properties and strength mechanism is essential for the future engineering application. Taking the pulp concentration and the mortar ages as the variables, we tested five groups of blocks for the compressive strength and flexural strength, and observed their microstructures with a scanning electronic microscope. The results indicated that the microstructure got dense if the added pulp had a concentration of about 0.3%, and thereby its flexural strength would significantly improve, while the hydration products agglomerated and the microstructure got loose if the added pulp had a concentration of more than 1.0%, which caused a substantial decline in flexural strength. Besides, the hydration reaction was hindered at the early stage due to the addition of the pulp; hence the early strength of the mortar is on the low side. According to the strength mechanism analysis, all the results are mainly attributed to the effects: "water-reduction", agglomeration and retarding, caused by the addition of the pulp. 糯米浆水泥砂浆是一种创造性的新型复合材料, 探讨其力学性能和强度机理, 对于未来的工程应用是一项十分必要的工作。为此, 以糯米浆浓度和砂浆龄期为变量, 展开5组糯米浆水泥砂浆试块的抗压与抗折性能对比试验和微观结构电镜分析。结果表明, 浓度处于0.3%左右的糯米浆的加入, 可以使后期的水泥砂浆微观结构趋于密实, 抗折强度显著提高; 而浓度大于1.0%的糯米浆的加入, 将使后期的水泥水化产物聚合成团, 微观结构松散, 抗折强度大幅下降; 这是因为随着糯米浆的加入, 可以阻碍早期水泥水化反应的进行, 从而使水泥砂浆早期强度偏低。分析机理可知, 这种现象是由于糯米浆的加入引起浆体产生"减水"作用、聚合作用与缓凝作用造成的。