EFFECT OF COARSE AGGREGATE PROPERTIES ON THE DUCTILITY OF LIGHTWEIGHT CONCRETES

This study presents the variation of the ductility of lightweight concrete made with cold-bonded fly ash aggregates, produced by cold-bonding process through the pelletization of moistened fly ash-cement mixture at room temperature. Lightweight concretes with and without silica fume were cast at 0.35 and 0.55 w/c ratios with fly ash pellets as coarse aggregate and natural sand as fine aggregate. Lightweight aggregate was incorporated into the mixes at 30, 45, and 60 percent of the total aggregate volume and with 9.5 and 16 mm maximum particle sizes, respectively. In this manner 24 concrete mixtures were designed and tested to evaluate the compressive strength, static elastic modulus, and splitting tensile strength. In addition, three-point bending tests on notched beams were conducted to determine the fracture toughness and the characteristic length as a measure of ductility. Test results have revealed that the ductility of the lightweight concretes increased with higher coarse aggregate volume content and larger particle size, and decreased with the use of silica fume and low w/c ratio in the concretes. Also, the characteristic length reduced with the increase in compressive strength as in normal weight concrete.

• INTRODUCTION

• EXPERIMENTAL DETAILS

• TEST RESULTS AND EVALUATION

• CONCLUSIONS

• REFERENCES