MECHANICAL PERFORMANCE OF RICE HUSK ASH

ABSTRACT

Geopolymer concrete (GPC) with nominal tension bars can provide a better construction system than Ordinary Portland Cement Concrete (OPCC) due to high sustainability, durability, and adequate strength. The research work utilizes an alternate material rich in silica such as rice husk ash (RHA) and palm oil fuel ash (POFA) as a binder in place of cement due to early strength development. In this research work, rice husk and empty palm oil fruit bunches were collected from the respective mills, fine and coarse aggregate were purchased from a nearby quarry site. The ash was subjected to calcination in a locally made furnace for an hour at a temperature between 7000C-8000C, cooled and grinded to fine particles with a grinding milling machine. The laboratory tests carried out on the respective raw materials include X-ray Fluorescence (XRF) analysis, particle size distribution and specific gravity. The tests carried out on Ordinary Portland cement concrete and experimental geopolymer concrete without cement include slump test, compressive strength test, flexural strength with two points loads and Rebound Hammer Test The research work showed that Geopolymer Concrete(GPC) with different Molarity(M) have a satisfactory strength compared with the Ordinary Portland cement concrete(OPCC) based on the mix and oxide composition of class N rice husk ash used in the research work. The compressive strengths of OPCC, RHA GPC M16, and RHA GPC M14 are 35N/mm2 , 28N/mm2 , 26.38N/mm2 respectively. Similarly, flexural strengths are 5.0N/mm2 , 4.39 N/mm2 and 4.10N/mm2 respectively. The strengths of GPC increases in the order of their molarity (M14 and M16) of sodium hydroxide. RHA GPC M16 is 6.16% higher than the compressive strength of RHA GPC M14 while palm oil fuel ash GPC M14 and M16 had a low compressive strength of 1.3N/mm2 and 2.25N/mm2 due to a low percentage of silica content and low silica-aluminium ratio which may be attributed to the duration of the ash in the furnace and cooling process. It further showed that the cost of producing a GPC is 41.1% higher than OPCC. The significance of the findings is that GPC has the potential to take over the concrete industry soon for flexural members in the presence of standard engineering code for practice.