Properties of lightweight and normal weight concretes with similar strength

This thesis addresses an experimental study conducted to investigate the performance of lightweight concrete (LWC) and normalweight concrete (NWC) with similar compressive strength. Lightweight concretes were produced with cold-bonded fly ash aggregates. For this, a dry powder mixture of 90% fly ash and 10% Portland cement by weight was pelletized through moistening in a revolving tilted pan at ambient temperature and cured for 28 days. A total of four concrete mixtures with designed compressive strengths of 25 and 45 MPa were developed for both LWC and NWC, namely LWC25, NWC25, LWC45 and NWC45. The concretes were tested at 28 and 56 days for water permeability, chloride ion permeability, gas permeability, and sorptivity index. On the other hand, compressive strength development of the concretes was observed at 7, 28, and 56 days. The results of comparing LWA with NWC indicated that the compressive strengths of both types of concrete for all ages were almost similar while water permeability of LWC generally slightly higher than that of NWC. Moreover, resistance to chloride penetration, gas permeability as well as sorptivity of LWCs was poorer than NWC.