Resistance to Chloride Penetration of Recycled Aggregate Concrete Modified Using Treated Coarse Recycled Concrete Aggregate and Fibres

This paper presents a study that aimed to assess the chloride penetration depth of recycled aggregate concrete (RAC) modified by using treated coarse recycled concrete aggregate (RCA), adding polyolefin (PO) or polypropylene (PP) fibre and comparing with normal concrete. The coupling effects of the treated RCA and fibres on the chloride penetration of RAC were analysed after two different curing regimes (i.e. normal and seawater) and tested at different curing ages (i.e. 90, 180 and 300 days). Results showed that the inclusion of treated coarse RCA can reduce porosity, thereby decreasing the chloride penetration of RAC. However, the coupling effects of treated coarse RCA and fibre, especially on the use of PO fibre, can enhance the results.

Performance of Self Compacting Concrete Incorporating Coarse Recycled Concrete Aggregates Exposed to Sulphate Attack

The interpretation of the performance of self-compacting concrete made with distinct proportion of coarse recycled concrete aggregate (RCA) (0%, 25%, 50%, 75% and 100%) exposed to sodium sulphate solution (50 gram/litre) under fully immersion condition is studied in this paper. Compressive and tensile strength development/degradation, mass change and length change under sulphate attack was surveyed for all tested units. According to the results it can be conclude that the use of coarse recycled concrete aggregate does not affect the development of strength of concrete with respect to natural material mixtures. It also conclude that for producing of sustainable and green concrete, the quality of used coarse recycled concrete aggregate is an important factor. The differ proportion of coarse recycled concrete aggregate & duration of immersion of concrete in sulphate solution also affect the concrete properties. Reusing recycled combination has twin property benefits: benefiting many tons dismantled concrete worldwide and conserving natural aggregates.

Bricks and Concrete Wastes as Coarse and Fine Aggregates in Sustainable Mortars

The total substitution by volume of natural coarse calcareous aggregate by coarse recycled brick aggregate (RBA) and coarse recycled concrete aggregate (RCA) has been investigated to produce more sustainable and environment-friendly mortars. Aggregates were also partially substituted by their fines at 12.5% by volume. Mortars have been tested in terms of mechanical, microstructural, and durability properties. Results show that it is feasible to replace a natural calcareous aggregate entirely by recycled aggregates. In particular, the obtained mortars, even if more porous and more prone to the water capillary absorption than that manufactured with natural aggregates, result in less stiffness and thus are less subjected to crack formation, more permeable to water vapour, and less susceptible to sulphate attack.