Characteristics of concrete produced with burnt clay as coarse aggregate

Abstract

Aggregate is the principal ingredient for concrete, and studies have predicted that excessive use of it would lead to insufficient quantity for future large constructions. This study investigate the use of burnt clay as alternative aggregates for concrete production. First clay was exposed to elevated temperature in the range of 1200 – 6000 C. Thereafter 3 sets of burnt clay aggregate were prepared then they were subjected to tests to determine the specific gravity, moisture content, water absorption, bulk density, impact value and crushing value test. These aggregates were subjected to compressive strength, impact value and crushing value tests. Result showed that the specific gravity of these aggregates exposed to between 600-1200^oC, were between 2.11- 2.43. Whereas the bulk densities were between 973.7-1012 kg/m³ for burnt clay aggregates exposed to between 600 -1200^oC. The moisture content of the burnt clay aggregates were in the range 1.749-1.833; Water absorption for the three sets of burnt clay aggregates was between 8.303-8.378 for clay aggregates heated to a range of 600-1200^oC. The compressive strength for the three types of 100mm concrete cubes produced using the burnt clay aggregates after 28 days of curing, were between 10-11.2 N/mm².While the compressive strength after 56days of curing, were between 13.20- 17.40N/mm² for concrete produced with burnt clay aggregates subjected to elevated temperatures of 600-1200^oC. The impact and crushing values of the crushed burnt clay aggregates ranges from 14- 33%. It was concluded that there is no significant difference between the quality of concrete produced with burnt clay aggregate and the conventional concrete (control sample). Hence, study recommended the use of burnt clay aggregate and durability properties of concrete be investigated.

Keywords: Coarse Aggregates, Properties, Concrete, Burnt Clay, Water Absorption