Strength properties of lightweight concrete made with basaltic pumice and fly ash

This paper presents a part of the results of an ongoing laboratory work carried out to design a structural lightweight concrete (SLWC) made with basaltic pumice (scoria) as aggregate and fly ash as mineral admixtures. A control lightweight concrete mixture made with lightweight basaltic pumice (scoria) containing only normal Portland cement (NPC), and with fly ash lightweight concrete mixture containing 20% of fly ash as a replacement of the cement in weight basis was prepared. Fly ash is used for economical and environmental concern. The concrete samples were cured at 65% relative humidity at 20 °C temperature. The compressive and flexural tensile strengths of hardened concrete, the properties of fresh concrete including density, and slump workability were measured. Laboratory compressive and tensile strength tests results showed that SLWC can be produced by the use of scoria. However, the use of fly ash seems to be necessary for the production of cheaper and environment-friendly SLWC with the compressive and tensile strengths similar to control SLWC containing only NPC.