The use of concrete wastes as a limestone replacement in limestone-blended cement production

Abstract

The limestone used in CEM II B-L type cement production is taken from nature routinely by quarrying of natural limestone resources which results in an ecological imbalance in the regions due to the destruction of nature. In this study, the use of concrete wastes in cement production is investigated. Experimental studies were carried out especially for their use in limestone blended cement production. For this purpose, concrete samples (150x150x150 mm) with a compressive strength of 65 MPa in average were milled after compression tests and milled concrete wastes were used instead of limestone additive in CEM II B-L type cement production. Their chemical and physical properties were investigated according to related cement standards. Also, the X-Ray diffraction analysis of cements were performed for the purpose of comparison. Mechanical performances of cements were evaluated at 2, 7 and 28 days under three point flexural and compressive tests. The use of waste concrete as limestone additive up to 10% replacement ratio increased the flexural strength by 8%. Also, the use of waste concrete up to 5% as limestone additive increased the compressive strength by 15, 8, and 9% at 2, 7 And 28 days, respectively. As conclusion, waste concretes can be successfully used instead of limestone additive in CEM II B-L type cement production.

Keywords

• Concrete waste
• cement production
• physical
• chemical
• strength