Experimental investigation on the viability of palm oil fuel ash as a sustainable additive in high performance concrete

ABSTRACT

The usage of by-products stems from industry offers a promising avenue for promoting clean production, waste minimization, and reducing greenhouse gas emissions, thus fostering environmental sustainability. This study delves into the performance evaluation of palm oil fuel ash (POFA) in concrete, aiming to assess its impact on strength, flowability, durability, and microstructure. The findings indicate that incorporating POFA into concrete mixes, up to a 12% dosage enhances compressive, flexural, and splitting tensile strengths. However, higher POFA content leads to decreased workability. Notably, the study divulges a significant control over chloride ingress with the addition of POFA, suggesting its potential to mitigate degradation in aggressive environments. Microstructural analysis of the specimens further highlights the promising role of POFA in enhancing concrete performance under adverse conditions, affirming its viability as a sustainable alternative in construction materials.

Keywords:
Palm oil fuel ash; By-products; Additive; Waste minimization; Sustainability

1. INTRODUCTION

The construction sector poses a substantial impact on environmental sustainability due to its extensive consumption of resources and continuous release of harmful gases like CO₂ into the atmosphere. To address this challenge and foster sustainability in building construction, researchers are turning to unconventional renewable resources [¹,²,³,⁴]. Palm oil fuel ash (POFA), a byproduct of the palm oil industry stems from burning waste materials such as shells and fibres in power plants. POFA is an unavoidable material which has been produced from the oil industry over several decades. Palm oil fuel ash can effectively replace certain quantity of cement in construction, thereby reducing the environmental impact of cement manufacturing and the issues related to its transportation [⁵,⁶,⁷,⁸,⁹,¹⁰].

The quantity of POFA produced is steadily increasing alongside the rise in palm oil production, imposing its utilization to avoid environmental challenges associated with waste accumulation. As society becomes increasingly aware of the environmental impacts of industrial and agricultural activities, there is a growing interest in finding sustainable solutions to utilize waste materials effectively [¹¹,¹²,¹³,¹⁴,¹⁵,¹⁶]. In the realm of construction, this interest has sparked a movement towards incorporating industrial and agricultural waste materials into concrete production to enhance sustainability. However, this movement is not only driven by environmental concerns but also by the urgent need to address the harmful residues that pose threats to human health and the environment [¹⁷,¹⁸,¹⁹,²⁰,²¹].

Industrial and agricultural processes generate significant amounts of waste, ranging from byproducts of manufacturing to residues from farming activities. If not managed properly, these residues can pollute water sources, contaminate soil, and release harmful gases into the atmosphere [²²,²³,²⁴,²⁵,²⁶]. Numerous studies highlight the benefits of incorporating agricultural waste materials into concrete, showcasing their superior properties compared to traditional cement, which emits high levels of CO₂. POFA, being environmentally friendly and requiring less energy during production, offers a sustainable alternative. Moreover, the usage of POFA with cement can reduce production costs but also minimize waste accumulation in landfills, thereby improving the environment [²⁷,²⁸,²⁹,³⁰,³¹,³²,³³].

Despite its potential, the use of POFA in concrete production requires careful consideration, as studies have shown a decrease in compressive strength when high percentages of cement are replaced with POFA, appropriate mix design should be done to obtain and maintain the quality of the concrete with suitable grades [³⁴,³⁵,³⁶,³⁷,³⁸,³⁹,⁴⁰,⁴¹,⁴²]. However, current research aims to enhance concrete properties while leveraging POFA’s ability to prevent and reduce chloride attacks, further demonstrating its promise as a sustainable solution in construction. Besides, the efforts to minimize waste generation through resource efficiency, recycling, and sustainable practices are critical for reducing the environmental footprint of industrial and agricultural activities.

2. MATERIALS AND TESTING METHODS

POFA is partially substituted for cement in concrete and different mixes were prepared. POFA has been substituted in the weight % of cement by 4 to 20% in the mortar. The samples were designated as PFA-4 to PFA-20 concerning the POFA content. The performance of POFA has been test verified.

2.1. Portland cement

Portland cement of grade 53 has been used throughout the study to examine the enactment of POFA with cement. Table 1 furnishes the composition of Portland cement.

Table 1
Composition of portland cement (%).

CONSTITUENT	% OF COMPOSITION
CaO	62.97
SiO2	23.06
Al2O3	5.86
Fe2O3	3.97
MgO	2.91
Na2O	0.21
K2O	0.19
SO3	0.22
LOI	0.89

2.1.2. Palm Oil Fly Ash

Table 2 provides a chemical composition of Palm Oil Fly Ash. SiO₂ may impart pozzalanic properties to POFA. However, the constituents of Palm Oil Fuel Ash are critically influenced by the raw material used in the industry.

Table 2
Chemical properties of POFA.

CONSTITUENT	% OF COMPOSITION
CaO	9.47
SiO2	62.6
Al2O3	4.83
Fe2O3	3.59
K2O	4.98
Na2O	0.88
SO3	0.95
MgO	4.73
LOI	7.97

2.2. Testing methods

• (1)

  Concrete slump test was conducted for the control and POFA added fresh concrete mix by IS 1199-2004 [⁴³].

• (2)

  Compressive, flexural and split tensile strength after 28 days of curing of specimens were calculated as per IS 516-2018 [⁴⁴].

• (3)

  Ultrasonic pulse velocity (USPV) test was performed as per IS: 13311 (Part 1) for the control and POFA-added concrete specimens [⁴⁵].

• (4)

  XRD analysis has been performed to study the microstructure properties of POFA concrete. Mix design was carried out as per IS 10262: 2019 [⁴⁶] and samples were prepared for the mix proportion of 1: 1.67: 3.14 for the water to binder ratio of 0.48.

3. RESULTS AND DISCUSSIONS

3.1. Compressive strength of PFA mixes

The capacity of the material to withstand load is mainly determined by compressive strength. The concrete specimens substituted with POFA were subjected to compressive pressure. It is evident that the addition of POFA to concrete increased its mechanical strength; however, the strength increase may be utilizing POFA up to 12% with cement. Mix PFA-12 attained a compressive strength of 24.5 MPa. Higher substitution of POFA reduces the strength after 28 days of curing, and the tested values are presented in Figure 1.

Figure 1
Compressive strength variations of POFA concrete.

Mix PFA-12 and PFA-20 gained the highest and lowest compressive strength respectively among all the mixes, whereas had the lowest strength among PFA mixes. The strength of the mixes PFA-4, PFA-8, and PFA-12 gained 4.18%, 9.76% and 13.95% higher compressive strength than the control mix respectively. Mixes PFA-16 and PFA-20 dropped by 6.52% and 11.36%, respectively, after 28 days. Test results indicated that POFA enhances strength attainment in the mix.

3.2. Flexural strength of PFA mixes

Flexural strength is predominantly considered in determining the structural integrity of cementitious ­composites. The presence of internal voids and capillary channels led to a decrease in the flexural strength of the control mix, indicating a weakening in concrete quality. The bonding capabilities of POFA considerably influenced the strength, with an increase in POFA percentage correlating with an increase in flexural strength. However, replacement of POFA beyond 12% exhibited lower strength development. The flexural strength was examined and the findings are shown in Figure 2.

Figure 2
Flexural strength variations of POFA concrete.

The flexural strength increase and decrease mirrored those observed in compressive strength variations. Besides, the cracking behaviour of POFA-admixed concrete under flexure was found almost the same as the control mix with slightly higher strength, suggesting that the relative effectiveness of pozzolanic materials primarily enhanced the flexural strength of the concrete matrix. Mixes PFA-4, PFA-8, and PFA-12 gained 2.9%, 10.4% and 16.4% higher flexural strength than control mix respectively. The provided image from the experimental findings (Figure 2) offers visual and quantitative insights into the behaviour of the tested specimens under flexure, further corroborating the observed trends in flexural strength variations.

3.3. Split tensile strength of PFA mixes

Split tensile strength reflects the strength of the bond between concrete elements. In Figure 3, the outcomes of the experimental investigation for POFA concrete are delineated. This investigation spans 28 days of curing and aims to scrutinize the enduring impact of POFA on the splitting tensile strength concrete. The regular concrete serves as a reference point for assessment, with the discrepancies in the tensile strength of POFA concrete depicted as percentages relative to the control mix.

Figure 3
Split tensile strength variations of POFA concrete.

Notably, compared with control concrete, up to 12% incorporation of POFA into the mix showed an escalation of splitting tensile strength by around 21% at the 28-day mark. However, beyond 12%, the increase in tensile strength surpassed that of mix PFA-12, Mixes PFA16 and PFA-20, surpassing that of mix PFA-12 by 13.4% and 29.6% respectively. This declining trend mirrors the observations made regarding compressive and flexural strength.

The primary reason behind the reduced tensile strength in higher replacement percentage of POFA in concrete is mainly governed by the weak bonding between cement pastes and POFA due to less content of cement, leading to concrete failure initiating at the vulnerable interface zone. Additionally, the higher water absorption nature of POFA reduces the normal quantity of water required for the hydration process.

3.4. Workability of PFA mixes

The effect of using POFA on the workability of mixes has been tested. Workability is a substantial property that affects the quality of concrete and in terms of slump, the workability of PFA mixes was calculated. It was observed that an increase in POFA in the mix reduced the workability of the concrete. This is evidenced by the decreasing slump values of the PFA mixes. For instance, when 4%, 8%, 12%, 16% and 20% of cement is replaced with POFA, compared with the control mix the slump values of PFA mixes decreased by 2.15%, 5.38%, 9.68%, 13.98% and 18.28% respectively. Figure 4 illustrates the slump variations of CC and PFA mixes.

Figure 4
Slump variations of CC and PFA mixes.

The decrease in workability with higher POFA replacement percentages can be attributed to several factors related to the physical characteristics of POFA. Firstly, POFA particles are finer in size. Finer particles have a larger surface area, which necessitates a larger amount of water to coat their surfaces. This reduces the overall W/C ratio in the mix, leading to lower workability. Besides, POFA particles may have higher porosity which allows them to absorb more water. This absorption further contributes to the reduction in the available water for lubricating the concrete mixture, resulting in decreased workability.

3.5. Ultrasonic Pulse Velocity (UPV) of PFA mixes

The impact of replacing cement with POFA on the ultrasonic pulse velocity of concrete specimens and the influence of the curing period have been test verified. If the replacement percentage of cement with POFA increases, there is a corresponding decrease in the UPV of the concrete specimens. The percentages given illustrate the extent of this decrease compared to the control mix. Figure 5 elucidates the UPV values of control and PFA mixes for various curing periods.

Figure 5
Ultrasonic pulse velocity values of control and PFA mixes.

It was observed that as the curing period increases, the ultrasonic pulse velocity of the specimens also increases. This indicates that over time, the concrete gains strength and density, leading to higher velocities. Irrespective of curing age and POFA content, PFA mixes exhibited higher ultrasonic pulse velocities than the control mix due to the pore-filling effect of POFA the mix, which reduces voids in the concrete specimens.

The decrease in ultrasonic pulse velocity with an increase in POFA content in concrete may be due to the lower density and higher fineness of POFA present in cement. POFA incorporation results in less porous concrete compared to control concrete due to their denser nature which results in higher ultrasonic pulse velocity values. This indirectly indicates that the durability of POFA-added concrete is more than control concrete.

3.6. Probability of corrosion of steel in PFA mix

From Figure 6 the Probability of corrosion of steel entrenched in the PFA-12 mix has been assessed in terms of half-cell potential values. PFA-12 mix is found optimal mix, hence it is considered for corrosion study. This method is commonly used in the field of corrosion to evaluate the possibility of corrosion occurring in reinforced concrete structures. The test results provide an indication of the electrochemical activity at the surface of the reinforcement steel within the concrete. A more negative half-cell potential specifies a higher probability of corrosion, while a less negative value suggests a lower probability.

Figure 6
Probability of corrosion of steel in PFA mix.

In this context, the passage notes that the half-cell potential values measured for the PFA-12 mix were lower than CC mix. This implies that the probability of corrosion over time in steel embedded in the POFA-12 mix is lesser than in the control concrete. The nonhomogeneous formation of hydrated products in the mix of PFA-12 contributed to corrosion reduction of steel. POFA reacts with Ca(OH)₂ in the presence of water to form C–S–H and C–A–H. These hydration products contribute to the densification of microstructure and lessen its overall porosity. Lower porosity restricts the ingress of aggressive agents such as moisture, oxygen, and chloride ions, which are primary contributors to the initiation and propagation of corrosion in reinforced concrete structures. By minimizing the availability of these corrosive agents, the risk of corrosion of embedded steel is significantly reduced.

3.7. X-ray diffraction (XRD) of Control and PFA concrete

The X-ray diffraction (XRD) patterns are illustrated in Figures 7 and 8. Figures show valuable insights into the crystalline composition of OPC and POFA concrete. XRD analysis was carried out for control and PFA-12 mixes. Quartz emerges as the predominant mineral exhibiting a crystalline structure, indicating its significant presence in both materials.

Figure 7
XRD of control concrete.

Figure 8
XRD of POFA added concrete.

Notably, the XRD analysis of POFA reveals prominent quartz intensity, registering approximately 3500 counts. Additionally, the presence of opal in POFA is identified, stemming from the calcination process of palm oil fibres and shells.

Both Figure 7 and 8, elucidate distinct diffraction peaks ranging from 16 to 32^°. This peak signifies crystalline silica and alumina compounds, respectively, indicating the influence of POFA on the crystalline composition of the concrete. Moreover, the presence of crystalline quartz and mullite phases is noted, further emphasizing the alterations induced by POFA incorporation. The XRD analysis indicates that the incorporation of POFA develops a stable crystalline structure in concrete.

The incorporation of POFA into OPC is imperative to address the low SiO₂ content inherent in OPC. Through the pozzolanic reaction, C–S–H is formed by the reaction of SiO₂ and Al₂O₃ with Ca(OH)₂ in the mix. Ca(OH)₂ serves as a pivotal pointer in pozzolanic reactions. An increase in fineness content leads to a decrease in Ca(OH)₂ content, thereby enhancing the durability of concrete [⁴⁷,⁴⁸,⁴⁹,⁵⁰,⁵¹,⁵²,⁵³].

4. CONCLUSIONS

The significant results obtained from the experimental investigations of this study can be summarized as follows:

• Including POFA in concrete mixes led to decreased workability, evident in lower slump values compared to the control mix.

• Mix PFA-12 emerged as the optimal mix, exhibiting a compressive strength increase of 13.95% compared to the control mix. However, higher POFA replacement adversely affected the strength at 28 days.

• Mix PFA-12 confirmed notable improvements in flexural and split tensile strengths, showing increases of 16.4% and 21% respectively over the control mix at 28 days.

• POFA enhanced the resistance of concrete mixes against chloride attacks, limiting the ingress of damaging particles into the concrete matrix, especially in chloride solutions.

• Examination of concrete specimens highlighted changes in hydration product nature, with POFA-incorporated specimens exhibiting a crystalline structure. This structure exhibited superior resistance to chemical attacks, resulting in enhanced strength compared to OPC mixes.

• The utilization of POFA shows possibilities in maintaining the integrity of concrete matrices in aggressive environments. Additionally, it contributes to waste material conservation, aligning with sustainability goals.

5. BIBLIOGRAPHY

• ^[1]
  JOHAN, N.H.S., KHALID, F.S., “Strength of concrete containing POFA and fine recycle concrete as partial cement replacement”, Recent Trends in Civil Engineering and Built Environment, v. 4, n. 2, pp. 126–134, Jul. 2023.
• ^[2]
  SOORAJ, V.M., SEETHAPATHI, M., “Strength properties of Palm Oil Fuel Ash (POFA) concrete”, Journal of University of Shanghai for Science and Technology, v. 24, n. 6, pp. 265–271, Jun. 2022.
• ^[3]
  UMAR, H., SULAIMAN, S., SAID, M., “Assessing the implementation levels of oil palm waste conversion methods in Malaysia and the challenges of commercialization: towards sustainable energy production”, Biomass and Bioenergy, v. 151, n. 2, pp. 106179, Aug. 2021. doi: http://doi.org/10.1016/j.biombioe.2021.106179.
  » https://doi.org/10.1016/j.biombioe.2021.106179
• ^[4]
  HAMADA, H.M., JOKHIO, G.A., AL-ATTAR, A., et al, “The use of palm oil clinker as a sustainable construction material: a review”, Cement and Concrete Composites, v. 106, pp. 103447, Feb. 2020. doi: http://doi.org/10.1016/j.cemconcomp.2019.103447.
  » https://doi.org/10.1016/j.cemconcomp.2019.103447
• ^[5]
  ASINOR, S., ANIM, O.S., “Assessing the strength of lightweight concrete using Oil Palm Shells (OPS) as coarse aggregates”, International Journal of Technology and Management Research, v. 1, n. 3, pp. 26–31, Mar. 2020. doi: http://doi.org/10.47127/ijtmr.v1i3.32.
  » https://doi.org/10.47127/ijtmr.v1i3.32
• ^[6]
  HOSSAIN, M.M., KARIM, M.R., ELAHI, M.M., et al, “Long-term durability properties of alkali-activated binders containing slag, fly ash, palm oil fuel ash and rice husk ash”, Construction & Building Materials, v. 251, pp. 119094, Aug. 2020. doi: http://doi.org/10.1016/j.conbuildmat.2020.119094.
  » https://doi.org/10.1016/j.conbuildmat.2020.119094
• ^[7]
  AWAL, A.S.M.A., SHEHU, I.A., “Evaluation of heat of hydration of concrete containing high volume palm oil fuel ash”, Fuel, v. 105, n. 2, pp. 728–731, Mar. 2013. doi: http://doi.org/10.1016/j.fuel.2012.10.020.
  » https://doi.org/10.1016/j.fuel.2012.10.020
• ^[8]
  MO, K.H., LING, T.C., ALENGARAM, U., et al, “Overview of supplementary cementitious materials usage in lightweight aggregate concrete”, Construction & Building Materials, v. 139, pp. 403–418, May. 2017. doi: http://doi.org/10.1016/j.conbuildmat.2017.02.081.
  » https://doi.org/10.1016/j.conbuildmat.2017.02.081
• ^[9]
  THOMAS, B.S., KUMAR, S., AREL, H.S., “Sustainable concrete containing palm oil fuel ash as a supplementary cementitious material-a review”, Renewable & Sustainable Energy Reviews, v. 80, pp. 550–561, May. 2017. doi: http://doi.org/10.1016/j.rser.2017.05.128.
  » https://doi.org/10.1016/j.rser.2017.05.128
• ^[10]
  MUSHTAQ, F., ABDULLAH, T.A.T., MAT, R., et al, “Optimization and characterization of bio-oil produced by microwave assisted pyrolysis of oil palm shell waste biomass with microwave absorber”, Bioresource Technology, v. 190, pp. 442–450, Mar. 2015. http://doi.org/10.1016/j.biortech.2015.02.055. PubMed PMID: 25794811.
  » https://doi.org/10.1016/j.biortech.2015.02.055
• ^[11]
  NAIK, T.R., “Sustainability of concrete construction”, Practice Periodical on Structural Design and Construction, v. 13, n. 2, pp. 98–103, May. 2008. doi: http://doi.org/10.1061/(ASCE)1084-0680(2008)13:2(98).
  » https://doi.org/10.1061/(ASCE)1084-0680(2008)13:2(98)
• ^[12]
  HUSSEIN HAMADA, M., GUL AHMED, J., “The present state of the use of palm oil fuel ash (POFA) in concrete-review”, Construction & Building Materials, v. 175, pp. 26–40, Mar. 2018. doi: http://doi.org/10.1016/j.conbuildmat.2018.03.227.
  » https://doi.org/10.1016/j.conbuildmat.2018.03.227
• ^[13]
  ARULRAJAH, A., MAGHOOLPILEHROOD, F., DISFANI, M., et al, “Spent coffee grounds as a non-structural embankment fill material: engineering and environmental considerations”, Journal of Cleaner Production, v. 72, pp. 181–186, Jun. 2014. doi: http://doi.org/10.1016/j.jclepro.2014.03.010.
  » https://doi.org/10.1016/j.jclepro.2014.03.010
• ^[14]
  LIM, S.K., TAN, C.S., LIM, O., et al, “Fresh and hardened properties of lightweight foamed concrete with palm oil fuel ash as filler”, Construction & Building Materials, v. 46, pp. 39–47, Sep. 2013. doi: http://doi.org/10.1016/j.conbuildmat.2013.04.015.
  » https://doi.org/10.1016/j.conbuildmat.2013.04.015
• ^[15]
  MIRZA, J., KHALID, N.H.A., HUSSIN, M.W., et al, “Effectiveness of palm oil fuel ash as micro-filler in polymer concrete”, Jurnal Teknologi, v. 77, n. 16, pp. 5–80, 2015. doi: http://doi.org/10.11113/jt.v77.6402.
  » https://doi.org/10.11113/jt.v77.6402
• ^[16]
  TANGCHIRAPAT, W., SAETING, T., JATURAPITAKKUL, C., et al, “Use of waste ash from palm oil industry in concrete”, Waste Management (New York, N.Y.), v. 27, n. 1, pp. 81–88, Feb. 2007. doi: http://doi.org/10.1016/j.wasman.2005.12.014. PubMed PMID: 16497498.
  » https://doi.org/10.1016/j.wasman.2005.12.014
• ^[17]
  ARUNVIVEK, G.K., RAMESHKUMAR, D., “Experimental investigation on feasibility of utilizing phosphogypsum in e-glass fiber-incorporated ceramic wall tile”, Journal of the Institution of Engineers Series A, v. 103, n. 2, pp. 445–451, 2022. doi: http://doi.org/10.1007/s40030-021-00604-2.
  » https://doi.org/10.1007/s40030-021-00604-2
• ^[18]
  SAFIUDDIN, M., ABDUS SALAM, M., JUMAAT, M.Z., “Utilization of palm oil fuel ash in concrete: a review”, Journal of Civil Engineering and Management, v. 17, n. 2, pp. 234–247, Jun. 2011. doi: http://doi.org/10.3846/13923730.2011.574450.
  » https://doi.org/10.3846/13923730.2011.574450
• ^[19]
  MEYER, C., “The greening of the concrete industry”, Cement and Concrete Composites, v. 31, n. 8, pp. 601–605, Sep. 2009. doi: http://doi.org/10.1016/j.cemconcomp.2008.12.010.
  » https://doi.org/10.1016/j.cemconcomp.2008.12.010
• ^[20]
  NAYAKA, R.R., ALENGARAM, U.J., JUMAAT, M., et al, “High volume cement replacement by environmental friendly industrial by-product palm oil clinker powder in cement-lime masonry mortar”, Journal of Cleaner Production, v. 190, pp. 272–284, Apr. 2018. doi: http://doi.org/10.1016/j.jclepro.2018.03.291.
  » https://doi.org/10.1016/j.jclepro.2018.03.291
• ^[21]
  RANJBAR, N., MEHRALI, M., ALENGARAM, U., et al, “Compressive strength and microstructural analysis of fly ash/palm oil fuel ash based geo polymer mortar under elevated temperatures”, Construction & Building Materials, v. 65, pp. 114–121, May. 2014. doi: http://doi.org/10.1016/j.conbuildmat.2014.04.064.
  » https://doi.org/10.1016/j.conbuildmat.2014.04.064
• ^[22]
  ARUNVIVEK, G.K., MAHESWARAN, G., KUMAR, S.S., “Eco-friendly solution to mitigate the toxic effects of hazardous construction industry waste by reusing in concrete for pollution control”, Nature Environment and Pollution Technology, v. 14, n. 4, pp. 963, 2015.
• ^[23]
  RUKZON, S., SIRIVIVATNANON, V., “Resistance to chloride penetration of blended Portland cement mortar containing palm oil fuel ash, rice husk ash and fly ash”, Construction & Building Materials, v. 22, n. 5, pp. 932–938, May. 2008. doi: http://doi.org/10.1016/j.conbuildmat.2006.12.001.
  » https://doi.org/10.1016/j.conbuildmat.2006.12.001
• ^[24]
  AL-KUTTI, W., ISLAM, A.B.M.S., NASIR, M., “Potential use of date palm ash in cement-based materials”, Journal of King Saud University -”, Engineering and Science, v. 31, n. 1, pp. 26–31, Feb. 2017.
• ^[25]
  RAJAK, M.A.A., MAJID, Z.A., ISMAIL, M., “Morphological characteristics of hardened cement pastes incorporating nano-palm oil fuel ash”, Procedia Manufacturing, v. 2, pp. 512–518, Dec. 2015. doi: http://doi.org/10.1016/j.promfg.2015.07.088.
  » https://doi.org/10.1016/j.promfg.2015.07.088
• ^[26]
  BLAISI, N.I., “Environmental assessment of utilizing date palm ash as partial replacement of cement in mortar”, Journal of Hazardous Materials, v. 357, pp. 175–179, Jun. 2018. doi: http://doi.org/10.1016/j.jhazmat.2018.06.013. PubMed PMID: 29886362.
  » https://doi.org/10.1016/j.jhazmat.2018.06.013
• ^[27]
  THOMAS, B.S., KUMAR, S., AREL, H.S., “Sustainable concrete containing palm oil fuel ash as a supplementary cementitious material: a review”, Renewable & Sustainable Energy Reviews, v. 80, pp. 550–561, Dec. 2017. doi: http://doi.org/10.1016/j.rser.2017.05.128.
  » https://doi.org/10.1016/j.rser.2017.05.128
• ^[28]
  DHARMARAJ, R., ARUNVIVEK, G.K., KARTHICK, A., et al, “Investigation of mechanical and durability properties of concrete mixed with water exposed to a magnetic field”, Advances in Civil Engineering, v. 2021, pp. 1–14, 2021. doi: http://doi.org/10.1155/2021/2821419.
  » https://doi.org/10.1155/2021/2821419
• ^[29]
  KHALID, N.H.A., HUSSIN, M.W., MIRZA, J., et al, “Palm oil fuel ash as potential green micro-filler in polymer concrete”, Construction & Building Materials, v. 102, pp. 950–960, 2016. doi: http://doi.org/10.1016/j.conbuildmat.2015.11.038.
  » https://doi.org/10.1016/j.conbuildmat.2015.11.038
• ^[30]
  TANGCHIRAPAT, W., KHAMKLAI, S., JATURAPITAKKUL, C., “Use of ground palm oil fuel ash to improve strength, sulfate resistance, and water permeability of concrete containing high amount of recycled concrete aggregates”, Materials & Design, v. 41, n. 1, pp. 150–157, Oct. 2012. doi: http://doi.org/10.1016/j.matdes.2012.04.054.
  » https://doi.org/10.1016/j.matdes.2012.04.054
• ^[31]
  ALTWAIR, N.M., JOHARI, M.A.M., HASHIM, S.F.S., “Flexural performance of green engineered cementitious composites containing high volume of palm oil fuel ash”, Construction & Building Materials, v. 25, n. 11, pp. 4287–4293, Nov. 2011.
• ^[32]
  SARAVANAKUMAR, R., REVATHI, V., “Some durability aspects of ambient cured bottom ash geopolymer concrete”, Archives of Civil Engineering, v. 63, n. 3, pp. 99–114, 2017. doi: http://doi.org/10.1515/ace-2017-0031.
  » https://doi.org/10.1515/ace-2017-0031
• ^[33]
  ARUNVIVEK, G.K., RAMESHKUMAR, D., “Incorporated Portland cement concrete”, Journal of The Institution of Engineers Series A, v. 100, pp. 611–618, 2019.
• ^[34]
  ALDAHDOOH, M.A.A., BUNNORI, N.M., JOHARI, M.A.M., “Development of green ultra-high performance fiber reinforced concrete containing ultrafine palm oil fuel ash”, Construction & Building Materials, v. 48, pp. 379–389, 2013. doi: http://doi.org/10.1016/j.conbuildmat.2013.07.007.
  » https://doi.org/10.1016/j.conbuildmat.2013.07.007
• ^[35]
  SARAVANAKUMAR, R., GOPI, R., ELANGO, K.S., et al, “Industrial waste phosphogypsum’s Impact onCO₂ reduction and global warming”, Global NEST Journal, v. 25, n. 9, pp. 127–132, 2023. doi: http://doi.org/10.30955/gnj.005198.
  » https://doi.org/10.30955/gnj.005198
• ^[36]
  ZEYAD, A.M., JOHARI, M.A.M., TAYEH, B.A., et al, “Pozzolanic reactivity of ultrafine palm oil fuel ash waste on strength and durability performances of high strength concrete”, Journal of Cleaner Production, v. 144, n. 40, pp. 511–522, Dec. 2016.
• ^[37]
  MUJAH, D., “Compressive strength and chloride resistance of grout containing ground palm oil fuel ash”, Journal of Cleaner Production, v. 112, pp. 712–722, Jul. 2016. doi: http://doi.org/10.1016/ j.jclepro.2015.07.066.
  » https://doi.org/10.1016/j.jclepro.2015.07.066
• ^[38]
  REVATHI, V., SARAVANAKUMAR, R., THAARRINI, J., “Effect of molar ratio of SiO₂/Na₂O, Na₂SiO₃/NaOH ratio and curing mode on the compressive strength of ground bottom ash geopolymer mortar”, International Journal of Earth Science and Engineering, v. 7, n. 4, pp. 1511–1516, 2014.
• ^[39]
  MEN, S., TANGCHIRAPAT, W., JATURAPITAKKUL, C., et al, “Strength, fluid transport and microstructure of high-strength concrete incorporating high-volume ground palm oil fuel ash blended with fly ash and limestone powder”, Journal of Building Engineering, v. 56, pp. 104714, Sep. 2022. doi: http://doi.org/10.1016/j.jobe.2022.104714.
  » https://doi.org/10.1016/j.jobe.2022.104714
• ^[40]
  HAMADA, H.M., ALATTAR, A.A., YAHAYA, F., et al, “Mechanical properties of semi-lightweight concrete containing nano-palm oil clinker powder”, Physics and Chemistry of the Earth Parts A/B/C, v. 121, pp. 102977, Jan. 2021. doi: http://doi.org/10.1016/j.pce.2021.102977.
  » https://doi.org/10.1016/j.pce.2021.102977
• ^[41]
  GOPI, R., SARAVANAKUMAR, R., ELANGO KRISHNAN, S., et al, “Influence of presaturated coconut fibre ash pellets in concrete”, Matéria (Rio de Janeiro), v. 28, n. 8, pp. e20230190, 2023.
• ^[42]
  RAMASAMY, S., DEIVASIGAMANI, V., SOUNDARARAJAN, E.K., et al, “Influence of nano-silica on impact resistance and durability of fly ash concrete in structural buildings”, Matéria (Rio de Janeiro), v. 29, n. 1, pp. e20230340, 2024. doi: http://doi.org/10.1590/1517-7076-rmat-2023-0340.
  » https://doi.org/10.1590/1517-7076-rmat-2023-0340
• ^[43]
  INDIAN STANDARD, IS 1199–2004: Method of sampling and analysis of concrete, New Delhi, IS, 2004.
• ^[44]
  INDIAN STANDARD, IS 516–2018: Method of Tests for Strength of Concrete, New Delhi, IS, 2018.
• ^[45]
  INDIAN STANDARD, IS 13311–1: Method of Non-destructive testing of concrete, New Delhi, IS, 1992.
• ^[46]
  INDIAN STANDARD, IS 10262–2019 Concrete Mix Proportioning — Guidelines, New Delhi, IS, 2019.
• ^[47]
  CHINDAPRASIRT, P., JATURAPITAKKUL, C., SINSIRI, T., “Effect of palm oil fuel ash fineness on packing effect and pozzolanic reaction of blended cement paste”, Procedia Engineering, v. 14, pp. 361–369, Dec. 2011. doi: http://doi.org/10.1016/j.proeng.2011.07.045.
  » https://doi.org/10.1016/j.proeng.2011.07.045
• ^[48]
  MOHAMMADHOSSEINI, H., YATIM, J.M., “Microstructure and residual properties of green concrete composites incorporating waste carpet fibers and palm oil fuel ash at elevated temperatures”, Journal of Cleaner Production, v. 144, n. 40, pp. 8–21, Feb. 2017. doi: http://doi.org/10.1016/j.jclepro.2016.12.168.
  » https://doi.org/10.1016/j.jclepro.2016.12.168
• ^[49]
  YUSUF, M.O., JOHARI, M.A.M., AHMAD, Z., “Strength and microstructure of alkali-activated binary blended binder containing palm oil fuel ash and ground blast-furnace slag”, Construction & Building Materials, v. 52, pp. 504–510, Feb. 2014. doi: http://doi.org/10.1016/j.conbuildmat.2013.11.012.
  » https://doi.org/10.1016/j.conbuildmat.2013.11.012
• ^[50]
  KUMAR, R.S., REVATHI, V. “Flexural behavior of bottom ash geopolymer reinforced concrete beams”, Asian Journal of Research in Social Sciences and Humanities, v. 6, n. 9, pp. 820–827, Sep. 2016. doi: http://doi.org/10.5958/2249-7315.2016.00834.0.
  » https://doi.org/10.5958/2249-7315.2016.00834.0
• ^[51]
  LIU, M.Y.J., ALENGARAM, U.J., SANTHANAM, M., et al, “Microstructural investigations of palm oil fuel ash and fly ash based binders in lightweight aggregate foamed geopolymer concrete”, Construction & Building Materials, v. 120, pp. 112–122, Sep. 2016. doi: http://doi.org/10.1016/j.conbuildmat.2016.05.076.
  » https://doi.org/10.1016/j.conbuildmat.2016.05.076
• ^[52]
  KARIM, M.R., ZAIN, M.F.M., JAMIL, M., et al, “Fabrication of a non-cement binder using slag, palm oil fuel ash and rice husk ash with sodium hydroxide”, Construction & Building Materials, v. 49, pp. 894–902, Dec. 2013. doi: http://doi.org/10.1016/j.conbuildmat.2013.08.077.
  » https://doi.org/10.1016/j.conbuildmat.2013.08.077
• ^[53]
  SARAVANAKUMAR, R., ELANGO, K.S., REVATHI, V., et al, “Influence of aggressive environment in macro and microstructural properties of bottom ash geopolymer concrete”, Sustainability (Basel), v. 16, n. 5, pp. 1732, 2024. doi: http://doi.org/10.3390/su16051732.
  » https://doi.org/10.3390/su16051732

Publication Dates

• Publication in this collection
  24 June 2024
• Date of issue
  2024

History

• Received
  01 Apr 2024
• Accepted
  24 Apr 2024