秸秆/聚丙烯纤维-玻化微珠保温混凝土抗冻融试验研究

Study on Freeze-Thaw Resistance of Straw/Polypropylene Fiber-Glazed Hollow Bead Insulation Concrete

为探索冻融循环下秸秆粉末、聚丙烯纤维和玻化微珠对保温混凝土导热性能的影响,采用正交试验设计16组保温混凝土并进行抗压强度、抗拉强度和导热系数的试验测试,分析秸秆粉末体积率(因素A)、玻化微珠代砂体积率(因素B)、聚丙烯纤维体积率(因素C)对秸秆/聚丙烯纤维-玻化微珠保温混凝土导热系数变化和质量损失的影响。结果表明,随冻融循环次数增加,混凝土隔热能力和质量均不断降低;80次冻融循环后导热系数平均增大49.97%,质量损失平均降低37.93%。极差分析表明,对导热系数的影响顺序为:因素A>因素B>因素C,对质量损失的影响顺序为:因素A>因素C>因素B。冻融循环下,秸秆纤维对保温混凝土导热系数、质量损失的影响较其他掺合料明显,并可有效延长热量传递路径,提高保温效果。

To explore the influence of straw powder,polypropylene fiber and glass beads on the thermal conductivity of insulated concrete under the freeze-thaw cycle,and the tests were carried out of the compressive strength,tensile strength and thermal conductivity in the 16 groups of insulating concrete which were designed by the orthogonal tests,and the effects of volume rate of straw powder(factor A),volume rate of glass bead substitute sand(factor B) and volume rate of polypropylene fiber(factor C) on the thermal conductivity of straw/polypropylene fiber-glass bead insulating concrete were completed.The results showed that the coefficient of thermal conductivity and mass loss of straw/polypropylene fiber-insulated concrete changed with the number of freeze-thaw cycles.The thermal conductivity and mass of concrete decreased with the increase of freeze-thaw cycles,with the thermal conductivity increasng by 49.97% and mass loss decreasing by 37.93% on average after 80 freeze-thaw cycles.Under the freezing and thawing cycle,the influence of straw fiber on the thermal conductivity and quality loss of thermal insulation concrete was more obvious than that of other admixtures,extending the heat transfer path and improving the heat insulation effect effectively.