Reinforced Concrete Slabs Containing Recycled Concrete as Coarse Aggregate

Abstract

<p>This research presents an experimental study on the performance of reinforced<br>recycled aggregate concrete (RAC) that contains one of two types of recycled coarse aggregate,<br>one from normal concrete and another from self – compacting concrete (SCC). The<br>replacement percentages (by weight) of natural coarse aggregate with the recycled coarse<br>aggregate are (0, 33.3, 66.7 & 100) % by weight. Moreover, Silica Fume was used as an<br>admixture for all (RAC) mixtures. Concrete compressive strength, split tensile strength, and<br>flexural strengths were studied for all of the reference and (RAC) mixtures at (28) days age, by<br>testing concrete cubes, cylinders and reinforced concrete slabs specimens respectively. The<br>results showed that the using of recycled waste concrete as concrete as aggregate will largely<br>decreasing the slabs flexure strength while using of recycled (SCC) mixtures have relatively<br>small effect in reducing the slabs flexure strength. The adding of silica fume to the concrete<br>mix will increasing the slabs flexural strength and that increase is larger for recycled (SCC)<br>aggregate mixtures than the recycled concrete aggregate mixtures. The results also indicate that<br>the compressive strength and tensile strength are decreased by different ratio when using of<br>recycled waste concrete as aggregate, while using of recycled (SCC) aggregate will also reduce<br>the tensile strength and the modulus of rupture while the compressive strength increased when<br>using this type of recycled aggregate. On the other hand, the mixtures with the Silica Fume<br>showed a significant enhancement in the mechanical properties compared to those without the<br>Silica Fume.</p>