水泥珊瑚砂浆的物理力学性能与微观结构特征分析

Analysis of physical properties and microstructural characteristics of cement-coral sand mortar

摘要:

本文研究了珊瑚砂-水泥砂浆的工作性能和机械性能，以及矿物掺合料对珊瑚砂浆的改性作用，并与标准砂-水泥砂浆进行对比，采用SEM-EDS、XRD和FTIR等表征手段对珊瑚砂浆的微观机理进行探讨。结果表明：珊瑚砂浆的力学强度低于标准砂浆，通过复合矿物掺合料可改善水泥石基体及界面过渡区的微观结构，提高珊瑚砂浆的力学性能，其28d抗压强度较标准砂浆提高2%。珊瑚砂凹凸不平的表面与硬化水泥浆体形成紧密结合的啮合状态，有助于提高砂浆的体积稳定性；珊瑚砂的内养护作用使砂浆的力学性能和抵抗收缩的能力得到提高。粉煤灰和矿粉的微集料填充作用和火山灰效应，提高了珊瑚砂浆的机械性能和抗氯离子扩散能力。珊瑚砂持续释放出的Ca2+、Mg2+离子参与了水泥的水化反应，有助于生成更多的水化产物。

Abstract:

Compared with standard sand mortar, this paper studies the work and mechanical performance of coral sand mortar, and the effects of mineral admixtures on the coral mortar. Then SEM-EDS, XRD and FTIR were used to explore microscopic mechanism of coral mortar. The study shows that mechanical strength of the coral mortar is lower than it of the standard sand mortar, and the mineral admixture can improve the microstructure of cement mortar and interface transition area, also the mechanical strength of coral mortar can be improved, the 28 d compressive strength of it than standard mortar increased by 2%. The uneven surface of coral sand can form a tight meshing state with hardened cement mortar, which is helpful to improve the volume stability of mortar. The internal curing effect of coral sand improves the mechanical properties and resistance to shrinkage of the mortar. Furthermore, micro–aggregate filling effect and volcanic ash effect of fly ash and slag improve the mechanical properties and the ability to resist chloride ion diffusion of the coral mortar. The continuous release of Ca2+ and Mg2+ ions from coral sand is involved in the hydration reaction of cement, which helps to generate more hydration products.