STRUCTURAL SEMI-LIGHTWEIGHT CONCRETE USING CRUSHED HOLLOW BLOCK (CHB) AS LIGHTWEIGHT AGGREGATE.

The properties of structural lightweight concrete produced using crushed hollow block as semi-lightweight coarse aggregate were investigated. The crushed hollow block (CHB) was treated by solution of silica fume and calcium hydroxide of different concentrations (10 and 20%) by weight of mixing water. The performance of semi-lightweight concrete made with treated CHB and containing silica fume as an additional cementitious material at different percents (0, 5, 10, 15 % by weight of cement) was investigated on terms of physical properties. Test results proved that , using treated artificial semi-lightweight aggregate increase the compressive and flexural strengths of concrete, the idea of using cured aggregate by pozzolanic material solution must be taken into consideration. The need of using supplementary cementitious materials such as silica fume must be detected to enhance the performance of semilightweight concrete