Thermal, physical and mechanical evaluation of concrete blocks with recycled expanded polystyrene

Abstract The research project produced concrete blocks with partial replacement of traditional coarse aggregate by recycled expanded polystyrene. Hence, an experimental dosage was proposed, associating the Compressible Packaging Model with Tango´s adapted methodology, published in 1994, to produce four types of blocks (one reference, without substitution, and three with content ratios of 5, 10 and 15% of partial volumetric replacement of coarse aggregate by expanded polystyrene), with a w/c ratio of 0,5. Tests were performed to check the physical and mechanical characteristics of the blocks, following NBR 12118:2013, demonstrating that the reference block and the one with 5% coarse aggregate partial replacement could be used for structural applications, while the blocks with 10 and 15% partial replacement did not meet the NBR 6136:2016 standard for minimum compressive strength. The analysis of the thermal performance of the blocks was done using the calculation procedures of NBR 15220-2:2005, verifying the limits established by NBR 15575-4:2013. The thermal comfort provided by the reference blocks and the blocks with 15% replacement in the masonry prototypes presented similar internal temperature results during the observed period. However, at times when the highest environment temperatures were recorded, the masonry with recycled polystyrene presented maximum delay and thermal inertia.

摘要 本研究项目以回收膨胀聚苯乙烯（recycled expanded polystyrene）部分替代传统粗骨料制备混凝土砌块。据此提出试验配合比设计方案，将可压缩包装模型（Compressible Packaging Model）与1994年发布的Tango改良方法相结合，用于制备四类砌块：1组为基准组（未进行骨料替代），其余3组分别以膨胀聚苯乙烯（expanded polystyrene）按体积占比5%、10%、15%部分替代粗骨料，且所有试件的水灰比均为0.5。
依据NBR 12118:2013标准开展试验以检测砌块的物理与力学性能，结果显示基准砌块与5%粗骨料部分替代砌块可应用于结构工程领域；而10%与15%替代率砌块未达到NBR 6136:2016标准规定的最小抗压强度要求。
采用NBR 15220-2:2005的计算流程对砌块的热工性能进行分析，验证其是否符合NBR 15575-4:2013设定的限值要求。针对砌体原型的热舒适性能测试表明，基准砌块与15%替代率砌块在观测周期内的内部温度表现相近；但在环境温度峰值时段，掺加回收聚苯乙烯的砌体展现出更显著的延迟隔热效果与更高的热惰性。