Strength, microstructure, and thermal conductivity of the insulation wallboards prepared with rice husk fiber and recycled concrete aggregates

This paper intends to evaluate the influence of content of rice husk fiber and cementitious materials on mechanical properties and thermal conductivity of thermal insulation wallboards. Thermal insulation wallboard contained different mass of rice husk fiber was prepared when the weight of cement, fly ash, cellulose ether, naphthalene superplasticizer, and recycled concrete aggregates was equal. Scanning electron microscopy (SEM) shows the internal structure of the insulation wallboards is very dense. Compared to thermal conductivity of blank group (0.9600 W/m·°C), B2 (0.1997 W/m·°C) and C2 (0.1810 W/m·°C) measured by the DRCD-3030 intelligent thermal conductivity tester can meet certain engineering requirements. Average compressive strength, flexural strength, and thermal conductivity of wallboards decreases with content of rice husk fiber increasing when other materials mass are the same. Under the same conditions of curing time and rice husk content, average compressive and flexural strength increase with the increase of the amount of cementitious material.本研究旨在评估稻壳纤维（rice husk fiber）掺量与胶凝材料（cementitious materials）用量对保温墙板力学性能与导热性能的影响。在固定水泥、粉煤灰、纤维素醚、萘系高效减水剂及再生混凝土骨料用量的前提下，制备了掺加不同质量稻壳纤维的保温墙板。扫描电子显微镜（SEM）观测结果显示，保温墙板的内部结构极为致密。与空白组的导热系数（0.9600 W/(m·℃)）相比，经DRCD-3030智能导热系数测试仪测得的B2组（0.1997 W/(m·℃)）与C2组（0.1810 W/(m·℃)）的导热系数均可满足一定工程应用需求。在其他材料用量固定的前提下，墙板的平均抗压强度、抗折强度与导热系数均随稻壳纤维掺量的增加而降低。在养护龄期与稻壳纤维掺量固定的条件下，墙板的平均抗压强度与抗折强度均随胶凝材料用量的增加而提升。