Sadagopan Madumita, Rivera Alexander Oliva, Malaga Katarina, Nagy Agnes
Department of Resource Recovery and Building Technology, University of Borås, 50190 Borås, Sweden.
RISE-Research Institutes of Sweden, 50115 Borås, Sweden.
Materials (Basel). 2023 Sep 27;16(19):6437. doi: 10.3390/ma16196437.
This paper investigates the fracture mechanical properties of concrete, using crushed concrete aggregates (CCA) and granulated blast furnace slag (GGBS) for partial cement replacement. CCAs made from prefabricated concrete replace 100% of the fine and coarse fractions in concrete recipes with / ratios of 0.42 and 0.48. Two pre-treatment methods, mechanical pre-processing (MPCCA) and accelerated carbonation (COCCA), are investigated for quality improvements in CCA. The resulting aggregates show an increased density, contributing to an increase in the concrete's compressive strength. The novelty of this paper is the superposition of the effects of the composite parts of concrete, the aggregate and the cement mortar, and their contributions to concrete fracture. Investigations are directed toward the influence of fine aggregates on mortar samples and the influence of the combination of coarse and fine aggregates on concrete samples. The physical and mechanical properties of the aggregates are correlated with mortar and concrete fracture properties. The results show that CCA concrete achieves 70% of the fracture energy values of concrete containing natural aggregates, and this value increases to 80% for GGBS mixes. At lower / ratios, MPCCA and COCCA concretes show similar fracture energies. COCCA fine aggregates are the most effective at strengthening the mortar phase, showing ductile concrete behavior at a / ratio of 0.48. MPCCA aggregates contribute to higher compressive strengths for / ratios of 0.42 and 0.48. Thus, mechanical pre-processing can be improved to produce CCA, which contributes to more ductile concrete behavior.
本文研究了使用碎混凝土骨料（CCA）和粒化高炉矿渣（GGBS）部分替代水泥时混凝土的断裂力学性能。由预制混凝土制成的CCA在水灰比为0.42和0.48的混凝土配方中替代了100%的细骨料和粗骨料。研究了两种预处理方法，即机械预处理（MPCCA）和加速碳化（COCCA），以改善CCA的质量。所得骨料的密度增加，有助于提高混凝土的抗压强度。本文的新颖之处在于叠加了混凝土的组成部分、骨料和水泥砂浆的影响及其对混凝土断裂的贡献。研究针对细骨料对砂浆样品的影响以及粗、细骨料组合对混凝土样品的影响。骨料的物理和力学性能与砂浆和混凝土的断裂性能相关。结果表明，CCA混凝土的断裂能值达到了含天然骨料混凝土的70%，对于GGBS混合料，该值增加到80%。在较低的水灰比下，MPCCA和COCCA混凝土表现出相似的断裂能。COCCA细骨料在增强砂浆相方面最有效，在水灰比为0.48时表现出延性混凝土行为。对于水灰比为0.42和0.48，MPCCA骨料有助于提高抗压强度。因此，可以改进机械预处理以生产CCA，这有助于使混凝土表现出更延性的行为。
