Abstract.

This study intends to find a way in order to increase the replacement content of natural coarse aggregates with raw materials by combining different types of waste coarse aggregates. For this aim, varying contents of recycled coarse aggregates (0%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 20%, 25% and 30%) from an old building demolish and untreated coal coarse aggregates (0%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 20%, 25% and 30%) are used as a replacement for natural coarse aggregates. A total of 19 mix designs with different contents of waste coarse aggregates are produced and compressive, tensile and flexural strengths as well as slump, the elastic modulus, dry unit weight, water absorption and expansion of concrete were measured. Consequently, some formulas are proposed to predict the mechanical performance of concrete based on the waste aggregates replacement contents. According to the obtained results, the optimal substituting ratio of recycled and untreated coarse aggregates in term of the highest compressive strength is obtained 5% while 15% of natural coarse aggregates could be replaced by a combination of both recycled and untreated coarse aggregates with the same content with no reduction in compressive strength.

摘要。

本研究旨在找到一种方法，通过结合不同类型的废粗骨料来增加天然粗骨料对原材料的替代含量。为此，从旧建筑物拆除和未经处理的粗煤中回收的粗骨料的含量各不相同（0％，2.5％，5％，7.5％，10％，12.5％，15％，20％，25％和30％）骨料（0％，2.5％，5％，7.5％，10％，12.5％，15％，20％，25％和30％）被用作天然粗骨料的替代品。总共制作了19种不同废料粗骨料含量的混合料设计，并测量了压缩，拉伸和弯曲强度以及坍落度，混凝土的弹性模量，干重，吸水率和膨胀率。所以，提出了一些基于废骨料替代含量的混凝土力学性能预测公式。根据获得的结果，获得最高抗压强度的再生和未处理粗骨料的最佳替代率为5％，而天然粗骨料的15％可以用相同的再生和未处理粗骨料的组合代替含量而抗压强度没有降低。