海泡石纤维增强高石粉含量机制砂砂浆性能的研究

以高石粉含量机制砂砂浆为研究对象,分析了海泡石纤维体积掺量和长度的变化对砂浆力学性能和干燥收缩的影响规律,并使用压汞仪和扫描电子显微镜研究了砂浆内部孔结构和微观形貌的变化特征。结果表明:适宜体积掺量的短海泡石纤维可显著改善砂浆的抗压强度、抗折强度和抗干燥收缩能力。与空白组相比,长度为1 mm的纤维体积掺量为1.5%时,试件28 d抗压强度和抗折强度分别提高98.9%和36.2%;长度为1 mm的纤维体积掺量为2.0%时,28 d自然干燥收缩值降低72.1%。海泡石纤维试件内部形成了大量针棒状钙矾石和片状氢氧化钙晶体,有效提高了砂浆硬化体系的密实性,砂浆总孔隙率与纤维掺量成反比。

Property of Sepiolite Fiber Reinforced Artificial Sand Mortar with High Stone Powder Content

The influences of sepiolite fiber volume fraction and length on mechanical properties and drying shrinkage of artificial sand mortar with high stone powder content were investigated. A mercury porosimeter and a scanning electron microscope were employed to analyse the characteristic variation of mortar internal pore structure and microscopic morphology. The results indicate that an appropriate quantity of short sepiolite fiber significantly improves the compressive strength, flexural strength and drying shrinkage resistance of mortar. Compared to the blank group, the 28 d compressive strength and flexural strength of specimens with 1.5% volume fraction of 1 mm length fiber increase by 98.9% and 36.2%, respectively. Besides, the 28 d natural drying shrinkage value with 2.0% volume fraction of 1 mm length fiber reduces by 72.1%. A large number of needle-shaped ettringite and flaky calcium hydroxide crystals are observed inside the sepiolite fiber specimen, which effectively improve the compactness of mortar hardening system. The total porosity of mortar is inversely proportional to the fiber volume fraction.