Volume 5, Issue 10 (November 2008)
Use of Ground Clay Brick as a Pozzolanic Material in Concrete
This study investigates the suitability of using ground clay brick (GCB) as a pozzolanic material in concrete. Crushed clay brick originating from demolished masonry was ground in the laboratory and used as a cement replacement in paste and concrete. Hydration characteristics of paste mixtures were investigated for a better understanding in concrete application. The effect of ground brick replacement for cement on concrete’s mechanical properties and chloride ion penetration resistance, as a measure of durability, were also studied. Two replacement levels, 15 % and 25 %, were compared with the control (0 % GCB). The study on the cementitious pastes showed that the ground brick slightly increased the water demand for normal consistency, delayed the time of setting, reduced the temperature rise during hydration, and decreased the calcium hydroxide (Ca(OH)2) content. The tests on concrete showed that the mechanical properties (i.e., compressive, flexural and splitting tensile strengths, and modulus of elasticity) of concrete containing ground brick were comparable to those of the concrete without GCB. Furthermore, the GCB increased the resistance of concrete to chloride ion penetration. The study undertaken proved that, when it is finely ground, clay brick obtained from demolished masonry can be recycled as a pozzolanic cementitious material in concrete.