Experimental Investigation on Rice Husk Ash Blended Concrete Performance in Terms of Compressive Strength

International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5379 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 Experimental Investigation on Rice Husk Ash Blended Concrete Performance in Terms of Compressive Strength Hussin Ahmad Hasrat1*, Bahirullah Rahmani1,2, Najeebullah Momand3, Naseer Agha Shirzad1, Sher Agha Akbari4 1Lecturer, Civil Department, Civil Engineering, Khurasan University, Nangarhar, Afghanistan 2Head, Research and Deployment Department, Khurasan University, Nangarhar, Afghanistan 3Department of Ecology and Nature Management, RUDN, University Moscow, Russia Federation 4Student, Civil Department, Civil Engineering, Khurasan University, Nangarhar, Afghanistan ABSTRACT: Concrete is the most widely used construction material globally, but its production relies heavily on Portland cement, contributing to significant CO₂ emissions and creating a substantial environmental burden. Rice husk ash (RHA), an abundant agricultural by-product with high silica content and pozzolanic potential, presents a promising opportunity for partial cement replacement, offering environmental and economic benefits. This study investigates the partial replacement of cement with RHA in concrete mixes, evaluating its effect on compressive strength. Concrete specimens were prepared with 0%, 5%, 10%, 15%, and 20% RHA replacement levels by weight, and compressive strength tests were conducted at 7 and 28 days. The gradual decrease in compressive strength with increasing RHA content is evident in the data. For the 28-day strength, the control mix registered 22.73 MPa, while the 5% RHA mix had 19.30 MPa, and the 20% RHA mix reported 13.92 MPa. Strength performance is optimal with a 5% replacement level, which is the closest to the control. This suggests the partial replacement of cement with RHA up to 5% is reasonably attainable, especially considering the marked reduction in cement content, which translates to a reduction in CO2 emissions, the recycling of agricultural waste, and the primary mechanical performance. KEYWORDS: Compressive Strength, Partial Cement Replacement, Pozzolanic Material, Rice Husk Ash, Sustainable Concrete, Waste Utilization. 1. INTRODUCTION The worldwide usage of concrete has grown exponentially, even if its production takes a hefty toll on the environment by relying on Portland cement, which accounts for a massive percentage of CO₂ emissions (Vijaya, Jagadeeswari, and Srinivas 2020)(Zareei et al. 2017)(Bixapathi and Saravanan 2022).Concerned about the sustainability of the construction industry, the limited use of cement due to its pozzolanic properties is being actively researched (Vijaya, Jagadeeswari, and Srinivas 2020)(Cavalcante et al. 2018). Incorporating such materials certainly advances the industry in terms of sustainability since it decreases cement usage as well as the cement industry’s carbon footprint (Jayaraman et al. 2023)(Zareei et al. 2017). As an agricultural by-product, rice husk ash (RHA) has even more potential use as an admixture to concrete due to its high pozzolanic silica content, availability, and global production (Lo, Lee, and Lo 2021)(Ozturk et al. 2020)(Rajashekhar Reddy, Harihanandh, and Murali 2021). The use of RHA, which is a by-product of the open burning of rice husks, will help in environmental sustainability of concrete production as well as RHA’s carbon negative status (Alex, Dhanalakshmi, and Ambedkar 2016)(Zareei et al. 2017). This practice minimizes the use of cement which in turn lowers the emission of CO₂, using agro-waste like RHA, and converting a useless product into a useful one which reduces waste in landfills (Vijaya, Jagadeeswari, and Srinivas 2020)(Mayooran, Ragavan, and Sathiparan 2017) (Alex, Dhanalakshmi, and Ambedkar 2016). From an environmental perspective, the cement industry’s CO₂ emissions and the subsequent production of concrete remains an environmental concern (Zareei et al. 2017)(Ali et al. 2021). This is because the construction industry remains overdependent on cement, which has a high carbon footprint (Mayooran, Ragavan, and Sathiparan 2017) (Zareei et al. 2017)(Tutur et al. 2023). This is of particular importance of developing countries, since RHA can be a low-cost, locally available alternative (Mayooran, Ragavan, and Sathiparan 2017)(Jayaraman et al. 2023)(Igba et al. 2019). For developing countries, this contributes to waste elimination and CO₂ emissions (Wang and Lee 2020) (Tutur et al. 2023). In addition, the concrete’s mechanical performance International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5380 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 may be compromised, since little is known regarding RHA’s optimal replacement levels (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018). RHA use helps reduce CO₂ cement production and has been said to provide “economic and environmental benefits that encourage the use of high-carbon RHA” (Mayooran, Ragavan, and Sathiparan 2017)(Zareei et al. 2017). Some prior studies did recognize the characteristics of RHA regarding its chemical, physical, and particle size properties, confirming its pozzolanic reactivity (Vijaya, Jagadeeswari, and Srinivas 2020) (Alex, Dhanalakshmi, and Ambedkar 2016)(Chia et al. 2020).RHA has 8590% amorphous silica, demonstrating its pozzolanic reactivity ability (Zareei et al. 2017) (Bixapathi and Saravanan 2022).An example of RHA having high silica content is 96.44% SiO₂ at calcination of 550°C, with high amorphous silica further enhancing pozzolanic reactions as well as C-S-H gel formation (Lo, Lee, and Lo 2021)(Hussein et al. 2025)(Samad et al. 2022).The pozzolanic activity of RHA enables the formation of C-S-H gel, which enhances strength, durability, and reduces the voids (Chia et al. 2020)(Samad et al. 2022).A number of studies have documented the improvements on compressive strength attributed to RHA and the partial replacement of cement, typically around the 10% replacement mark which resulted in strength enhancements of 19.6% at 28 days (Hussein et al. 2025)(Krishna, Sandeep, and Mini 2016).Moreover, other researches report optimal replacement values to be between 5% and 15% (Zareei et al. 2017)(Fapohunda, Akinbile, and Shittu 2017).As an example, one study confirmed that a 10% RHA replacement increased compressive strength, while replacements beyond 10% led to a reduction due to a porous structure (Ozturk et al. 2020). Research on paver blocks similarly confirms that an optimal RHA content of 10–15% can improve strength while maintaining performance (Kumar and Gopi 2022).Reported benefits include improved compressive strength at optimal partial replacement levels and a reduced heat of hydration (Wang and Lee 2020)(Chia et al. 2020). Moreover, the current state of the art incorporates contradictions at the empirical level of high replacement and the exploration of the ‘ever-lasting’ literature at the performance and durability levels in the following studies(Ma et al. 2023)(Syahida Adnan et al. 2021).The prominent gap and limitation of the research done is explaining RHA, in all its forms, above higher replacement levels, as the results are inconsistent starting above 10-20% in the literature (Mayooran, Ragavan, and Sathiparan 2017)(Hussein et al. 2025) (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018).The absence of a broader performance range and prolonged durability respectively, in the literature is noticed as most studies have been done with the 7/28 day curing and hence not field-based studies (Vijaya, Jagadeeswari, and Srinivas 2020) (Lo, Lee, and Lo 2021)(Ma et al. 2024) (Tutur et al. 2023).Significant research topics have been insufficiently covered, notably the durability and long-range performance of a concrete or compound, as most research is confined to certain concrete grades and/or relatively brief testing periods(Bixapathi and Saravanan 2022) (Rajashekhar Reddy, Harihanandh, and Murali 2021)(Igba et al. 2019).Furthermore, there is a lack of consensus on sustainable replacement thresholds that do not compromise concrete performance, particularly concerning the trade-off between strength gain and potential permeability reduction at higher replacement levels(Hussein et al. 2025)(Khankhaje et al. 2025). Many studies are limited to specific concrete grades or lack long-term durability data, such as tests for sulfate attack or freeze-thaw cycles, and some research is focused on specialized applications like radiation shielding or evaluating fresh properties for 3D printing concrete without assessing compressive strength, leaving a gap in comprehensive mechanical property analysis for standard structural concrete(Jayaraman et al. 2023)(Alrowaili et al. 2024)(Syahida Adnan et al. 2021)(Samad et al. 2022). A significant research gap identified is the limited data on reinforced concrete behavior, such as the shear or bending responses of RHA beams and slabs, necessitating further research(Fapohunda, Akinbile, and Shittu 2017). Furthermore, numerous investigations concluded that a key limitation is the lack of clarity on the behavior of RHA at higher replacement levels, with studies showing a linear strength reduction beyond 10-15%(Krishna, Sandeep, and Mini 2016)(Igba et al. 2019). This results in no clear consensus on sustainable replacement thresholds that do not compromise concrete performance(Hussein et al. 2025) (Ma et al. 2023). This study aims to contribute to filling this gap by assessing the effects of various RHA replacement levels on the compressive strength of concrete. The aim of the current study is to assess the effects of RHA replacement levels—specifically 0%, 5%, 10%, 15%, and 20%—on the compressive strength of concrete(Cavalcante et al. 2018). The scope is laboratory-based, focusing on tests for 7-day and 28-day compressive strength only, with durability, shrinkage, and field performance excluded(Bixapathi and Saravanan 2022) (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018)(Igba et al. 2019). The ultimate goal is to identify the optimal sustainable replacement level of RHA in cement without compromising strength, thereby contributing to cost savings, waste utilization, and reduced environmental impact(Vijaya, Jagadeeswari, and Srinivas 2020) (Krishna, Sandeep, and Mini 2016). International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5381 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 2. METHODOLOGY An experimental research design was utilized in this investigation which sought to ascertain the impact of the partial replacement of cement with Rice Husk Ash (RHA) on concrete's compressive strength. Methodologies involved the preparation of the materials, design of the mixes, casting and curing of the specimens, and the testing followed the relevant international standards. 2.1 Materials The choices for the materials in this study were made with ASTM, IS, and BS standards in mind, and the primary binder used was Ordinary Portland Cement (OPC) from the stallion brand. The Rice Husk Ash (RHA) was obtained from Laghman Province, burnt in an RHA oven, and pure ash was taken to the Khurasan University laboratory. For processing the RHA, a No. 4 sieve (4.75 mm) was used and then the RHA was ground to attain a fine particle size for increased pozzolanic activity. Other studies have also used RHA which was sieved, for example, at <125µm (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018), <20µm (Wang and Lee 2020), or <90μ (Mukilan et al. 2020), and frequently ground to improve reactivity. Fine and coarse aggregates were obtained from Sara Road District, Zangal Bagh. The coarse aggregate size was 20 mm and the Los Angeles abrasion value was 24.36%. The mixing and curing water was potable borewell water obtained from Khurasan University. 2.2 Mix Proportions The mix design was conducted using the ACI Method 318. A constant water-cement ratio of 0.5 was maintained for all mixes. Cement was partially replaced with RHA at levels of 0% (control), 5%, 10%, 15%, and 20% by weight. One trial mix was conducted for each proportion. For each mix, six cylindrical specimens (150 mm diameter × 300 mm height) were cast: three were designated for testing at 7 days and three at 28 days. The detailed mix proportions and measured slump values are presented in Table 1. The mix designs in other reviewed studies also commonly tested replacement levels up to 20-30%(Wang and Lee 2020) (Tutur et al. 2023). Table 1:Mix Proportions of Concrete Specimens with Partial Replacement of Cement by Rice Husk Ash (RHA) International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5382 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 2.3 Experimental Program and Test Procedures Figure 1: Schematic Diagram for Rice Husk Ash Mixed Concrete Simples 2.3.1 Batching, Mixing, and Workability Testing All materials were measured by weight in kilograms. Mixing was performed manually following a specific sequence: coarse aggregate was added first, followed by fine aggregate, then cement, with dry mixing conducted before the addition of water. Mixing continued until a uniform consistency was achieved. The workability of each fresh concrete mix was assessed immediately after mixing using the slump cone test in accordance with ASTM C143. The tests were conducted at an ambient temperature of approximately 25 °C. The results, as shown in Table 1, indicated slump values of 25.4 mm for mixes M1 through M3 and 50.8 mm for mixes M4 and M5. Figure 2:Materials: a) Raw Rice Husk, b) Rice Husk Ash, c) Cement ,d) Sand and e) Coarse Aggregate International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5383 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 2.3.2 Casting, Compaction, and Curing The concrete was then cast into cylindrical molds (150 mm diameter × 300 mm height) and compacted manually to remove voids. The specimens were kept in their molds for more than 24 hours before demolding. After demolding, the specimens were cured in water tanks at the Khurasan University laboratory. The curing water temperature was maintained at 25 ± 3 °C for the specified durations of 7 and 28 days. 2.3.3 Compressive Strength Testing The compressive strength was determined using a digital compression testing machine following the procedures outlined in ASTM C39. The loading rate was applied as per the ASTM specifications. Testing was performed on the cylindrical specimens after 7 and 28 days of curing. Three specimens from each mix were tested at each age, and the results were averaged. The compressive strength results are summarized in Table 3. Figure 3:a) Specimen during compressive Strength testing, b) Specimen after testing and d) Specimen in curing tank. 2.3.4 Additional Observations and Environmental Conditions No cracks, segregation, or other anomalies were reported during the mixing, casting, curing, or testing phases. There were no deviations from the planned standards or procedures. All laboratory activities were conducted at a stable ambient temperature of approximately 25 °C. 3. RESULTS AND DISCUSSION 3.1 Scope of Tests Five concrete mixes were tested, corresponding to RHA replacement levels of 0% (control), 5%, 10%, 15%, and 20% by weight of cement. The properties evaluated included workability (slump test) and compressive strength at 7 and 28 days. The mix identification was based on the RHA replacement percentage (M1 for 0% RHA, M2 for 5% RHA, etc.). 3.2 Workability (Slump) The workability of the fresh concrete mixes, measured by the slump test, showed a notable trend across the replacement levels. The slump value remained consistent at 25.4 mm for the control mix (0% RHA) and mixes with 5% and 10% RHA replacement. However, a significant increase in slump to 50.8 mm was observed for mixes with 15% and 20% RHA. This increase in workability at higher replacement percentages contrasts with the general trend noted in the literature, where RHA's high surface area typically leads to a reduction in workability(Kumar and Gopi 2022) (Rajashekhar Reddy, Harihanandh, and Murali 2021). The observed trend is consistent with a study that noted the use of a superplasticizer to maintain workability in mixes containing blended pozzolans (Vijaya, Jagadeeswari, and Srinivas 2020). Another study also emphasized adjusting water content to maintain a fixed slump when incorporating RHA (Mayooran, Ragavan, and Sathiparan 2017). The anomalous result in this study may be attributed to variations in the water demand, the specific particle morphology, the water-reducing agents used in the mix design, or the specific characteristics of the RHA used(Cavalcante et al. 2018) (Bixapathi and Saravanan 2022). International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5384 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 Table 2: Slump flow with RHA incorporation Figure 4: Slump flow of concrete with Different Replacement levels of RHA 3.3 Compressive Strength 3.3.1 Numerical Trends The compressive strength results for all mixes at 7 and 28 days are summarized in Table 3. A progressive decrease in strength was observed with increasing RHA content at both testing ages. The 7-day compressive strength dropped from 14.10 MPa for the control mix (0% RHA) to 5.98 MPa for the mix with 20% RHA. Similarly, the 28-day strength decreased from 22.73 MPa (0% RHA) to 13.92 MPa (20% RHA). The results indicate that even a 5% replacement (M2) led to a reduction in strength, with values of 10.80 MPa at 7 days and 19.30 MPa at 28 days, though this reduction was minimal compared to higher replacement levels. Table 3:Compressive Strength Test Results 25.4 25.4 25.4 50.8 50.8 M1(0% RHA) M2(5% RHA) M3(10% RHA) M4(15% RHA) M5(20% RHA) SLUMP FLOW (MM) CONCRETE MIX International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5385 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 Figure 5: Compressive Strength of RHA Concrete Mixes at 7 and 28 Days Figure 6: Strength Reduction from Control (Rice Husk Ash) 14.1 10.8 8.43 7.3 5.98 22.7 19.3 16.5 14.5 13.92 M1(0% RHA) M2(5% RHA) M3(10% RHA) M4(15% RHA) M5(20% RHA) COMPRESSIVE STRENGTH (MPA) CONCRETE MIX 28 Days Stress (Mpa) 7 Days Stress (Mpa) 14.1 10.8 8.43 7.3 5.98 22.7 19.3 16.5 14.5 13.92 0 5 10 15 20 25 30 35 40 M1(0% RHA) M2(5% RHA) M3(10% RHA) M4(15% RHA) M5(20% RHA) COMPRESSIVE STRENGTH (MPA) CONCRETE MIX 7 Days Stress (Mpa) 28 Days Stress (Mpa) International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5386 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 Figure 7: Strength Trend vs Rice Husk Ash % Table 4:Optimal Replacement Levels of Cement with Rice Husk Ash (RHA) Table 5:Percentage Reduction in Compressive Strength at 7 and 28 Days 5.98 7.3 8.43 10.8 14.1 13.92 14.5 16.5 19.3 22.7 0 5 10 15 20 25 30 35 40 M5(20% RHA) M4(15% RHA) M3(10% RHA) M2(5% RHA) M1(0% RHA) REDUCTION (MPA) CONCRETE MIX 7 Days Stress (Mpa) 28 Days Stress (Mpa) International Journal of Current Science Research and Review ISSN: 2581-8341 Volume 08 Issue 10 October 2025 DOI: 10.47191/ijcsrr/V8-i10-46, Impact Factor: 8.048 IJCSRR @ 2025 www.ijcsrr.org 5387 *Corresponding Author: Hussin Ahmad Hasrat Volume 08 Issue 10 October 2025 Available at: www.ijcsrr.org Page No. 5379-5391 Figure 8:Percentage Reduction in Compressive Strength at 7 and 28 Days 3.3.2 Mechanism and Explanation The reduction in compressive strength with higher RHA content is primarily attributed to the dilution effect, where cement, the primary binding agent, is partially replaced by a less reactive material, and the slower pozzolanic activity of RHA compared to the immediate hydration of cement(Vijaya, Jagadeeswari, and Srinivas 2020) (Bixapathi and Saravanan 2022) (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018). Although RHA possesses pozzolanic properties, its reaction with calcium hydroxide is slower than the primary hydration of cement, leading to lower early-age strength gains(Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018) (Wang and Lee 2020). The high silica content and pozzolanic reactivity of RHA contribute to secondary reactions that form additional C-S-H gel, but this process is more time-dependent(Vijaya, Jagadeeswari, and Srinivas 2020) (Hussein et al. 2025). The minimal strength loss observed at the 5% replacement level indicates a balance where the pozzolanic benefits partially offset the dilution effect, making it a tolerable partial replacement (Vijaya, Jagadeeswari, and Srinivas 2020) (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018). 3.3.3 Comparison with Literature The finding that a 5% RHA replacement maintains strength close to the control mix aligns with several studies(Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018). For instance, one investigation reported that a 5% replacement of cement by RHA and Bamboo Leaf Ash (BLA) resulted in a 1.84% strength increase at 28 days(Munish and Mehta 2024). This supports the consensus that moderate RHA substitution (≤10%) can maintain acceptable strength (Zareei et al. 2017)(Khankhaje et al. 2025)(Krishna, Sandeep, and Mini 2016). However, the significant strength reduction observed in this study at replacements above 10% contrasts with reports where finer RHA or optimized burning conditions yielded higher reactivity, allowing for larger replacement percentages while maintaining or enhancing strength (Vijaya, Jagadeeswari, and Srinivas 2020) (Ouypornprasert, Traitruengtatsana, and Kamollertvara 2018). For example, peak strength was observed at 15% RHA(Bixapathi and Saravanan 2022), 10% RHA(Kumar and Gopi 2022)(Ali et al. 2021), and 7.5% RHA(Rajashekhar Reddy, Harihanandh, and Murali 2021) in other studies. One study found that 10% RHA replacement led to a 19.6% increase in 28-day strength, while 20% RHA resulted in a 6.9% increase(Hussein et al. 2025). This discrepancy underscores the impact of factors like the pozzolanic reactivity of the RHA, which is greatly influenced by its source, which includes processing factors such as fineness and burning conditions , the grade of concrete, and the available other supplementary materials (Ozturk et al. 2020) (Rajashekhar Reddy, Harihanandh, and Murali 2021) (Fapohunda, Akinbile, and Shittu 2017). 0.0% 23.4% 40.2% 48.2% 57.6% 0.0% 15.0% 27.3% 36.1% 38.7% M1(0% RHA) M2(5% RHA) M3(10% RHA) M4(15% RHA) M5(20% RHA) STRENGTH REDUCTION (%) CONCRETE MIX % Reduction (28 days) % Reduction (7 days)