Low CO2 Concrete Made from Calcium Carbide Residue, Palm Oil Fuel Ash, Rice Husk-Bark Ash, and Recycled Aggregates

In this study, the low CO2 concrete was made by using several industrial wastes in both binder and aggregates. Calcium carbide residue (CCR) mixed separately with palm oil fuel ash (PA) and rice husk-bark ash (RA), and was used as a binder instead of Portland cement in the concrete mixture. Furthermore, fine and coarse recycled aggregates were fully replaced natural aggregates in order to cast concrete specimens (CCR-PA and CCR-RA concretes). Concrete properties namely compressive strength, chloride migration, and water permeability of CCR-PA and CCR-RA concretes were evaluated and compared with the conventional concrete (CON concrete). The results indicated that the compressive strengths of CCR-PA and CCR-RA concretes tended to increase with the curing age and development of compressive strength was similar to that of CON concrete. Introduction of small amount of Portland cement (OPC) as a strength accelerator resulted in effective enhancement of compressive strengths of CCR-PA and CCR-RA concretes. CCR-RA concrete contained 20% of OPC had the highest compressive strength of 34.4 and 40.9 MPa at 28 and 90 days, respectively. This compressive strength could be achieved by using 90 kg/m(3) of OPC. It was also found that the chloride migration and water permeability coefficient values of CCR-PA and CCR-RA concretes were similar to or lower than those of CON concrete. Moreover, the use of CCR-PA and CCR-RA binders in the concrete mixtures effectively improved the chloride migration and water permeability coefficient values of recycled aggregate concrete. These results also suggested that CCR-PA and CCR-RA concretes can be used as a new environmental friendly concrete because of these concretes can reduce as much as CO2 emissions and environmental problems.