Utilization of Palm Oil Fuel Ash in Concrete: A Review / Palmi Aliejaus Kuro Pelenų Naudojimas Betone. Apžvalga

Abstract

Uncontrolled dumping of palm oil fuel ash (POFA) not only occupies valuable land but also creates environmental pollution and health hazard. These problems can be reduced to a large extent by using POFA in concrete. A number of research works have been carried out to investigate the potential of POFA for use as a supplementary cementing material in normal, high strength, high performance, and aerated concretes. This paper presents a review on the use of POFA in different types of concrete. It firstly discusses the physical and chemical properties of POFA. Then the emphasis has been given on the effects of POFA on the fresh and hardened properties, and durability of concrete. This paper shows that both ground and unground POFA increase the water demand and thus decrease the workability of concrete. However, ground POFA has shown a good potential for improving the hardened properties and durability of concrete due to its satisfactory micro-filling ability and pozzolanic activity. In addition to discussing the benefits of POFA, this study has identified certain gaps in the present state of knowledge on POFA concrete, and listed several research needs for future investigation. The findings of this study would encourage the use of POFA as a supplementary cementing material for concrete. Santrauka Nekontroliuojami palmių aliejaus kuro pelenų (POFA) sąvartynai ne tik užima vertingus žemės plotus, bet ir teršia aplinką bei kelia pavojų sveikatai. Šios problemos gali būti sumažintos POFA naudojant betone. Daug mokslinių tyrimų buvo atlikta siekiant ištirti POFA potencialą, kad juos būtų galima naudoti kaip papildomą normalių, didelio stiprio, aukštos kokybės ir poringujų betonų cementavimo medžiagą. Šiame straipsnyje apžvelgiama, kaip POFA naudojami įvairių tipų betonams. Visų pirma aptariamos fizinės ir cheminės POFA savybės. Tuomet dėmesys atkreipiamas į šviežio ir sukietėjusio betono savybes bei betono ilgaamžiškuma. Šis straipsnis parodo, kad tiek malti, tiek nemalti POFA padidina vandens poreikį ir blogina technologines charakteristikas. Tačiau malti POFA parodė potencialą gerinant betono atsparumo ir ilgaamžiškumo savybes, nes jie pasižymi geromis mikroužpildų savybėmis ir pucolaniniu aktyvumu. Be to, aptarta POFA nauda, nustatytos tam tikros šiuo metu turimų žinių apie POFA betoną spragos ir išvardyta daugelis tyrimų, kurie turėtų būti atlikti ateityje. Šio darbo išvados turėtųpaskatinti naudoti POFA kaip papildomą rišamąją betono medžiagą.

Development of Self-Consolidating High Strength Concrete Incorporating Treated Palm Oil Fuel Ash

“…Similar findings on high-performance concrete containing high-volume fly ash were reported by Malhotra et al [11]. However, several previous studies reported that one of the challenges faced is the reduction of concrete workability as the POFA content increases [15,19,20,21]. In addition, a recent research conducted on the self-compacting concrete containing ground POFA up to 20% cement replacement showed that, as the percentage of replacement increased, the slump flow of concrete decreased, as shown in Figure 3 [22,23].…”

“…Whereas, there was a reduction in the compressive strength at 30% and 50% replacement levels of about 9% and 21% at three days, and 7% and 10% at seven days, respectively. As shown in Figure 10, the improvement at the early age compressive strength for concretes containing 10% and 20% treated POFA can be mainly attributed to the high fineness of the treated POFA, which acts as a micro-filler between the particles of cement and fills the voids and improves the microstructure of the concrete [15,29], while, at higher replacement levels (30% and 50%), it showed a reduction in compressive strength. The reduction in compressive strength is mainly due to the huge reduction in the cement content [14,30].…”

“…It was stated that, in 2007, approximately three million tons of POFA was produced in Malaysia and around 100,000 tons in Thailand [14]. This ash is landfill dumped without any beneficial returns [15]. Several studies have been conducted to check the feasibility of using ground POFA as a supplementary cementitious material (SCM) in concrete [3,12,13,16].…”

Modeling of Compressive Strength for Self-Consolidating High-Strength Concrete Incorporating Palm Oil Fuel Ash

“…The research outcomes confirmed that finely ground POFA can be used successfully as a supplementary cementing material (SCM) for producing various types of concrete. This has been substantiated by the findings of Safiuddin et al [9], Karim et al [10], Ranjbar et al [11] and Kabir et al [12]. However, no comprehensive research was conducted to explore the potential of POFA for the production of self-consolidating high-strength concrete (SCHSC).…”

“…This waste is used in generating electrical energy for milling operations and domestic or estate use in the palm oil mills [6,7]. After combustion, approximately 5% ash by weight of waste is produced [8,9]; this ash is referred to as palm oil fuel ash (POFA). Usually, POFA is dumped in an open field near the palm oil mills, thus creating environmental pollution and a health hazard [3,8,10].…”