Date of Publication
3-16-2026
Document Type
Master's Thesis
Degree Name
Bachelor of Science in Civil Engineering (Honors) - Ladderized
Subject Categories
Civil Engineering
College
Gokongwei College of Engineering
Department/Unit
Civil Engineering
Thesis Advisor
De Jesus, Richard
Concha, Nolan
Defense Panel Chair
Valdez, Rainier Lawrence
Defense Panel Member
Jarder, Samantha Louise
Garciano, Lessandro Estelito
Abstract (English)
Existing studies on rice husk biochar (RHB) in cementitious materials have largely focused on impervious concrete systems and chemical carbonation. Consequently, the role of physically adsorbed CO₂ in highly porous materials such as pervious concrete remains insufficiently explored. This study investigated the incorporation of rice husk biochar (RHB) as a partial cement replacement in pervious concrete and evaluated the relationships among RHB content, aggregate-to-cement (A/C) ratio, porosity, and carbon sequestration performance. RHB was produced through pyrolysis and characterized using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX) and X-ray fluorescence (XRF) to assess its suitability as a supplementary cementitious material. Pervious concrete specimens were prepared with RHB replacement levels of 0%, 10%, and 20% and A/C ratios of 4:1 for Mix Group A and 6:1 for Mix Group B. The specimens were subjected to early-age carbonation curing in an enclosed chamber. Carbonation was verified using phenolphthalein indicator testing, while carbonated areas were quantified through digital image analysis using ImageJ software. CO₂ uptake of pervious concrete was evaluated using the CO₂ concentration data log from curing and thermogravimetric analysis (TGA). Porosity was then measured using the water displacement method. Statistical analyses, including two-way ANOVA and linear regression, were conducted to examine relationships among the variables. Results showed that increasing RHB content increased the carbonated area and chemically absorbed CO₂ within the cementitious matrix for Mix Group A and Mix Group B. Conversely, physically adsorbed CO₂ decreased with increasing RHB content, indicating that CO₂ uptake occurred predominantly through chemical carbonation reactions. Porosity also decreased with increasing RHB content for both mix groups. At the 5% significance level, statistical analysis indicated that RHB content, aggregate-to-cement ratio, and their interaction had no statistically significant effect on porosity, indicating that they can be utilized individually. Overall, the findings indicate that rice husk biochar showed a strong potential as a sustainable cement replacement for enhancing carbon sequestration in pervious concrete.
Abstract Format
html
Abstract (Filipino)
Ang mga umiiral na pag-aaral hinggil sa rice husk biochar (RHB) sa mga pansimentong materyales ay higit na nakatuon sa mga impervious concrete system at kemikal na carbonation. Dahil dito, hindi sapat ang kaalaman sa papel ng pisikal na adsorption ng carbon dioxide (CO₂) sa mga concrete na may mataas na porosity, tulad ng pervious concrete. Sinuri ng pag-aaral na ito ang paggamit ng RHB bilang bahagyang pamalit sa semento sa pervious concrete at tinasa ang mga ugnayan sa pagitan ng porsyento ng RHB, aggregate-to-cement (A/C) ratio, porosity, at pag-sequester ng CO₂. Ang RHB ay ginawa sa pamamagitan ng pyrolysis at isinailalim sa characterization gamit ang scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDX) at X-ray fluorescence (XRF) upang masuri ang pagiging angkop nito bilang supplementary cementitious material. Ang mga specimen ng pervious concrete ay inihanda gamit ang 0%, 10%, at 20% na replacement level ng RHB at A/C ratio na 4:1 para sa Mix Group A at 6:1 para sa Mix Group B. Ang mga specimen ay isinailalim sa early-age carbonation curing sa loob ng isang enclosed chamber. Ang carbonation ay sinuri gamit ang phenolphthalein indicator testing, habang ang mga carbonated area ay sinukat sa pamamagitan ng digital image analysis gamit ang ImageJ software. Ang CO₂ uptake ng pervious concrete ay sinuri gamit ang CO₂ concentration data log mula sa proseso ng curing at thermogravimetric analysis (TGA). Sinukat naman ang porosity gamit ang water displacement method. Isinagawa rin ang mga estadistikal na pagsusuri, kabilang ang two-way ANOVA at linear regression, upang matukoy ang mga ugnayan sa pagitan ng mga variable. Ipinakita ng mga resulta na ang pagtaas ng nilalaman ng RHB ay nagdulot ng pagtaas sa carbonated area at chemically absorbed CO₂ sa loob ng cementitious matrix para sa Mix Group A at Mix Group B. Sa kabilang banda, bumaba ang physically adsorbed CO₂ habang tumataas ang nilalaman ng RHB, na nagpapahiwatig na ang CO₂ uptake ay pangunahing naganap sa pamamagitan ng mga kemikal na reaksyon ng carbonation. Bumaba rin ang porosity kasabay ng pagtaas ng nilalaman ng RHB para sa parehong mix group. Sa antas ng significance na 5%, ipinakita ng estadistikal na pagsusuri na ang nilalaman ng RHB, aggregate-to-cement ratio, at ang kanilang interaction ay walang statistically significant na epekto sa porosity, na nagpapahiwatig na maaari silang gamitin nang magkakahiwalay sa paghalo ng pervious concrete. Sa pangkalahatan, ipinapakita ng mga resulta na ang rice husk biochar ay may malaking potensyal bilang sustainable na pamalit sa semento para sa pagpapahusay ng carbon sequestration sa pervious concrete.
Abstract Format
html
Language
English
Format
Electronic
Keywords
Sustainable construction
Recommended Citation
Carlos, C. F. (2026). Investigation of carbon sequestration potential of pervious concrete with risk husk biochar. Retrieved from https://animorepository.dlsu.edu.ph/etdm_civ/71
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Embargo Period
3-16-2027
