Experimental studies on self-compacting concrete mixed with palm oil fuel ash and fly ash

Brabha Hari Nagaratnam (2016) Experimental studies on self-compacting concrete mixed with palm oil fuel ash and fly ash. Doctoral thesis, Universiti Malaysia Sabah.

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Abstract

Self-compacting concrete (SCC) is an innovative construction material that is competent to flow, filling all areas and corners of the formwork even in the presence of congested reinforcement under its own self-weight. Compared to normally vibrated concrete (NVC), SCC enhances productivity, working conditions and reduces the number of labourers due to the elimination of compaction. SCC has high powder content and thus it is necessary to replace some of the cement by pozzolanic admixtures to achieve an economical and durable concrete. This thesis presents a study on the utilization of agricultural and industrial wastes such as palm oil fuel ash (POFA) and fly ash (FA) as pozzolans in SCC with blended aggregates. The control mixture contained Ordinary Portland Cement (OPC) as the binder at 540 kg/m3 while the remaining mixtures incorporated binary and ternary blends of OPC, POFA and FA. The wastes replacement was in the range of 0 to 40% by weight of cement and water to binder (w/b) ratio was at 0.35 to 0.44. Super-plasticiser (SP) content was kept at a minimum of around 1%. Workability i.e. passing ability, filling ability and segregation resistance was determined and semi-adiabatic temperature rise during the initial stage of hydration was measured. It was observed that FA mixes required the least amount of SP to obtain a workable SCC; however, POFA mixes needed higher w/b ratio and SP content. The ternary use of POFA and FA in equal portions (TNY) had better workability properties than the POFA mixes and performed the best in terms of segregation resistance. The observed workability such as filling ability passing ability and segregation resistance were about 750 mm in slump diameter, less than 10 mm for step height, and less than 2% segregation ratio; indicating a highly workable SCC. The SCC with POFA mixes had the lowest amount of heat dissipation with peak temperatures of 57.9°C. The TNY mixes had lower heat dissipation compared to FA only mixes at 58.4°C. The hardened SCC was tested for the cube and cylinder compressive strength and splitting tensile strength for up to 90 days. The developed 28 days cylinder compressive strength for 40% POFA, FA and TNY mix were 25.3, 37.4 and 35.2 MPa, respectively, and were identified as medium strength concrete and is suitable for conventional concrete structures. The tensile strength at 28 days was around 3 MPa. The durability properties were determined using water absorption, sorptivity, and chloride penetration (RCPT and salt ponding tests) for up to 90 days. The durability properties; water absorption ≤ 6%, initial sorptivity of ≤ 0.02 mm/s1/2, RCPT ≤ 1000 Coulombs and salt concentration of ≤ 0.04% of concrete weight in SCM with 40% replacement indicate significant improvement in durability. Furthermore, the cost analysis shows that the material cost for SCC utilising FA can be comparable to the local NVC and cheaper than conventional SCC using European or Japanese mix design. In conclusion, the experimental studies indicate that SCC with binary and ternary blends of POFA and FA has significant potential as medium strength concrete when considering a sustainable construction material, hence also providing a cleaner production solution for the palm oil and coal power industry.

Item Type:	Thesis (Doctoral)
Keyword:	Self-compacting concrete, SCC, Palm oil, Fuel
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA1-2040 Engineering (General). Civil engineering (General) > TA401-492 Materials of engineering and construction. Mechanics of materials
Department:	FACULTY > Faculty of Engineering
Depositing User:	DG MASNIAH AHMAD -
Date Deposited:	31 Jul 2024 11:50
Last Modified:	31 Jul 2024 11:50
URI:	https://eprints.ums.edu.my/id/eprint/39291

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