Performance of rice husk ash (RHA) as partial cement replacement in peat stabilization using the mass stabilization method
A study on the stabilization of sapric peat was conducted to determine its physical, chemical and engineering properties. Peat is a problematic soil that incorporates low strength and stores high carbon. Due to these issues, cement stabilization is employed to enhance peat performance. However, peat...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | en |
| Published: |
Elsevier Ltd
2026
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| Subjects: | |
| Online Access: | https://umpir.ump.edu.my/id/eprint/46661/1/Performance%20of%20rice%20husk%20ash%20%28RHA%29%20as%20partial%20cement%20replacement%20in%20peat.pdf https://doi.org/10.1016/j.nxmate.2025.101525 https://umpir.ump.edu.my/id/eprint/46661/ |
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| Summary: | A study on the stabilization of sapric peat was conducted to determine its physical, chemical and engineering properties. Peat is a problematic soil that incorporates low strength and stores high carbon. Due to these issues, cement stabilization is employed to enhance peat performance. However, peat requires a significantly higher cement dosage, which raises environmental concerns due to the carbon-intensive nature of cement production. To address this, Rice Husk Ash (RHA), an abundant agro-industrial by-product was proposed as a partial substitute for Ordinary Portland Cement (OPC). An optimum binder dosage of 500 kg/m³ (SC100) was adopted as the control mix to prevent retards of cement hydration. Four additional mix designs incorporated partial cement replacement with RHA at 5 %, 10 %, 15 %, and 20 % by weight. The results demonstrated that RHA replacement up to 15 % yielded superior Unconfined Compressive Strength (UCS) across all curing durations (7, 28 and 60 days). In contrast, a 20 % RHA replacement (80 % cement) led to a notable decline in UCS, performing below the 5 % and 10 % RHA mixes. Microstructural analysis using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) revealed that the optimal 15 % RHA mix exhibited a strength increase from 50.41 kPa at 28 days to 61.29 kPa at 60 days. This improvement is attributed to the formation of calcium silicate hydrate (CSH) and the reduction of micropores, which collectively enhance matrix densification. EDX results indicated an increase in calcium (Ca) content and a corresponding decrease in carbon (C) content with extended curing, confirming the progression of cement hydration and pozzolanic reactions. It can be seen through the micrographs image; the RHA effectively filled the voids and improved the microstructure. However, based on visual absence in the micrograph, the secondary pozzolanic products such as calcium alumina silicate hydrate (CASH) and ettringite were not detected, likely due to the highly decomposed nature of sapric peat. This limitation underscores the challenges of stabilizing sapric peat, despite the mechanical benefits achieved. Overall, the incorporation of 15 % RHA presents a sustainable and technically viable approach to enhancing the engineering performance of tropical peat while reducing cement dependency |
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