Abstract:
This paper determines mix proportions and properties of Structural Lightweight High Strength Concrete (SLWHSC) made using lightweight aggregates and silica fumes. In the mixtures, three different materials were used as lightweight aggregates which are Expanded Slate, Expanded Shale and Over Burnt Bricks. These aggregates were used to replace normal weight coarse aggregate in concrete. These aggregates had specific gravities in range of 1.5 to 1.9. The concrete mix design was adjusted by replacing 10% of the cement with silica fume to gain high strength. SLWHSC samples were made with and without silica fume to compare the results with normal weight concrete. A number of cylinder specimens were casted to measure compressive and splitting tensile strength. The behavior of stress-strain of concrete mixtures was also studied. Results were astonishing as SLWHSC had 20% less weight and 75% more compressive strength than a normal weight concrete of 150 pcf weight and 4000 psi strength. Over burnt bricks and Expanded Shale proved to be suitable for SLWHSC. The SLWHSC produced had unit weight 115-120 pcf and compressive strength 6000-7000 psi. SLWHSC with reduced dead load and increased strength can be used for high rise structures and bridges.
