Some Properties of Self Consolidating Concrete Produced by Recycled Concrete Aggregates

A lot of countries are producing Self-Consolidating Concrete (SCC), also called Self-compacting Concrete that has many advantages compared to normal concrete. No specific or standard mix for achieving SCC is fixed nowadays. Meanwhile, some recommendations are indicated such the water to binder ratios should be less than 0.5, and the mixes should contain lower coarse aggregates and higher paste content comparing with conventional mixtures. The present research shows the results and analysis of experimental tests carried out to study the properties of self-consolidating concrete based on using two types of aggregates: normal (SCC) and recycled (RA-SCC). While the referring test corresponding to the use of normal recycled aggregates in the mix of SCC is fixed, the tests related to recycled aggregates self-consolidating concrete cover different mixes according to the amount of recycled aggregates per ratio to the normal aggregates content. The principal aim of this research is to improve the materials sustainability since the use of recycled aggregates will reduce the demand on the normal aggregates resulting from quarries. The scientific objective is to determine the effect of using recycled aggregates on the behavior of the SCC, also the possibility of using completely recycled aggregates instead of normal aggregates in the SCC mix. This study is composed of three parts. The first part is based on preparing the mixes of SCC and RA-SCC with local available aggregates in Lebanon. The second part is based on studying the effect of using different amounts of recycled aggregates on SCC by testing the workability of SCC and RA-SCC fresh mixes using slump test. The final part concerns the tests related to some hardened properties of SCC and RA-SCC such as compressive strength, flexural strength, and durability, using two types of equipment’s: the destructive and non-destructive such as Schmidt hammer and pundit tests. The results have shown that the presence of recycled aggregate improves some properties of the SCC for special amounts. On the other hand the presence of recycled aggregate had a negative effect on the rheological properties of the SCC by reducing the workability of concrete, because recycled aggregate absorb more water than normal one. The most important result is the possibility to use 100% recycled aggregates in the composition of self-consolidating concrete which improves the sustainability in the green construction. Keywords: Self Consolidating Concrete, Recycled aggregates, Compressive strength, Flexural strength, Durability, Pundit test, Schmidt hammer.