含水率与干湿循环对蒸压轻质混凝土抗压强度的影响

为研究水分对蒸压轻质混凝土力学性能的影响规律,开展了不同含水率和干湿循环次数蒸压轻质混凝土砌块的单轴压缩试验、X射线衍射(X-ray diffraction,XRD)试验和微观分析,得到了不同含水率和干湿循环次数下蒸压轻质混凝土抗压强度和弹性模量,并探讨抗压强度、弹性模量与含水率、干湿循环次数之间的变化规律.结果 表明:抗压强度和弹性模量在含水率从0增加到20％时,先快速降低,后降低速率变得缓慢并趋于稳定;随着干湿循环次数增加,水化反应在不断进行,水化产物不断增多,但干燥收缩作用也在不断加强,故导致抗压强度和弹性模量呈先增加后下降的趋势.

Influence of Moisture Content and Dry-wet Cycle on Compressive Strength of Autoclaved Lightweight Concrete

To study the influence of moisture content on mechanical properties of autoclaved lightweight concrete, uniaxial compression tests, X-ray diffraction (XRD) tests and microscopic analysis were carried out for autoclaved lightweight concrete blocks in different moisture contents and after various dry-wet cycles. Then corresponding compressive strength and elastic modulus of autoclaved lightweight concrete are obtained, and the variation of compressive strength and elastic modulus with moisture content and dry-wet cycle are investigated. The results show that when moisture content increases from 0% to 20%, both compressive strength and elastic modulus first decrease rapidly, then the decreasing rate becomes slow and the compressive strength comes to a constant value. With the increase of dry and wet cycles, the hydration reaction keeps going and the hydration products increases, while the drying shrinkage is strengthened. Hence, both compressive strength and elastic modulus first increase then decrease with the increase of dry and wet cycles.