Evaluation of the effects of rice husk ash and clay brick powder on the strength of high performance fiber reinforced concrete using response surface methodology

Abstract

This paper presents a study on the effects of rice husk ash and clay brick powder on compressive strength and flexural strength of high performance fiber reinforced concrete (HPFRC) at 28-day age using response surface methodology. The weight of silica fume using in HPFRC was replaced by rice husk ash from 10% to 40%, while fly ash was substituted by clay brick powder at range of 20% to 80%. Thirteen mixtures of HPFRC were prepared based on central composite design of response surface methodology in order to investigate the compressive strength and flexural strength of HPFRC at 28-day age. The result indicated that combination of fly ash and clay brick powder can be produced UHPFRC which have the compressive strength and flexural strength as much as those of the control. For example, using 18% rice husk ash combined with 49% clay brick powder; or 19% rice husk ash combined with 80% clay brick powder; or 23% rice husk ash combined with 65% clay brick powder; or 34% rice husk ash combined with 35.5% clay brick powder can be made HPFRCs that attained the 28-day compressive strength of 100 MPa and 28-day flexural strength of 32.5 MPa. Additionally, the compressive and flexural strength of HPFRC containing 40% rice husk ash and 80% clay brick powder were higher than those of the HPFRC control at 28-day age. Furthermore, there was no change in compressvie and flexural behaviours of the HPFRC containing rice husk ash and clay brick powder. Two models displayed the relationship between compressive strength/ flexural strength and defection were established in this study.

Keywords: High performance fiber reinforced concrete; strength; clay brick; response surface methodology; rice husk ash.