Date of Publication
8-2026
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
Cheryl Lyne C. Roxas
Defense Panel Chair
Daniel Nichol Valerio
Defense Panel Member
Maria Emilia Sevilla
Jason Maximino Ongpeng
Abstract (English)
The increasing demand for sustainable construction materials has encouraged the utilization of recycled concrete aggregates (RCA) as a partial or complete replacement for natural aggregates in concrete production. This study investigated the effects of RCA treatment method and RCA replacement level on the mechanical performance of concrete for batching plant and pumpcrete applications. Mechanical treatment, phosphoric acid treatment, acetic acid treatment, and untreated RCA were evaluated at replacement levels ranging from 0% to 100%. The influence of Class C fly ash and Type G superplasticizer on slump and 28-day compressive strength was also assessed.
Results showed that phosphoric acid-treated and mechanically treated RCA generally produced higher compressive strengths than untreated and acetic acid-treated RCA. However, RCA replacement level did not exhibit a consistent effect on compressive strength, as both low and high replacement levels produced high-strength concrete. Analysis of variance (ANOVA) indicated that RCA replacement percentage and RCA treatment method were not statistically significant factors within the investigated range, while fly ash and superplasticizer inclusion significantly influenced compressive strength. Several concrete mixtures exceeded 60 MPa, demonstrating the viability of RCA concrete for structural applications.
Microstructural and chemical analyses using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDX) revealed that the high-strength mix exhibited a denser and more compact microstructure with a lower Ca–Si proportion, indicating enhanced pozzolanic activity and secondary C–S–H formation. These characteristics were associated with improved compressive strength performance.
Response Surface Methodology (RSM) was used to develop predictive models and determine an optimum concrete mix design. The optimized mixture, consisting of 100% RCA, phosphoric acid treatment, Class C fly ash, and Type G superplasticizer, achieved a predicted compressive strength of 62.88 MPa while maintaining a slump of 8 in, satisfying the target performance criteria. The findings demonstrate the technical feasibility of utilizing treated RCA in concrete production and provide insights into the optimization of RCA-based concrete mixtures for practical construction applications.
Abstract Format
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Abstract (Filipino)
Ang patuloy na pagtaas ng pangangailangan para sa mga napapanatiling materyales sa konstruksyon ay nagbigay-daan sa paggamit ng recycled concrete aggregates (RCA) bilang bahagya o ganap na pamalit sa natural aggregates sa paggawa ng kongkreto. Sinuri sa pag-aaral na ito ang mga epekto ng paraan ng paggamot sa RCA at antas ng pagpapalit gamit ang RCA sa mekanikal na pagganap ng kongkreto para sa mga aplikasyon sa batching plant at pumpcrete. Sinuri ang mechanical treatment, phosphoric acid treatment, acetic acid treatment, at untreated RCA sa mga antas ng pagpapalit mula 0% hanggang 100%. Sinuri rin ang impluwensiya ng Class C fly ash at Type G superplasticizer sa slump at 28-araw na compressive strength.
Ipinakita ng mga resulta na ang RCA na ginamot gamit ang phosphoric acid at mechanical treatment ay karaniwang nagkaroon ng mas mataas na compressive strength kumpara sa untreated at acetic acid-treated RCA. Gayunpaman, hindi nagpakita ng pare-parehong epekto sa compressive strength ang antas ng pagpapalit ng RCA, sapagkat kapwa ang mababa at mataas na replacement levels ay nakagawa ng high-strength concrete. Ipinakita ng analysis of variance (ANOVA) na ang porsiyento ng RCA replacement at paraan ng RCA treatment ay hindi statistically significant na mga salik sa loob ng saklaw na sinuri, samantalang ang paggamit ng fly ash at superplasticizer ay may makabuluhang impluwensiya sa compressive strength. Ilang concrete mixtures ang lumampas sa 60 MPa, na nagpapakita ng potensiyal ng RCA concrete para sa structural applications.
Ipinakita ng microstructural at kemikal na pagususiri gamit ang Scanning Electron Microscopy (SEM) at Energy-Dispersive X-ray Spectroscopy (EDX) na ang high-strength mix ay may mas siksik at mas compact na microstructure at mas mababang Ca–Si proportion, na nagpapahiwatig ng mas mataas na pozzolanic activity at pagbuo ng secondary C–S–H. Ang mga katangiang ito ay iniugnay sa mas mahusay na compressive strength performance.
Ginamit ang Response Surface Methodology (RSM) upang bumuo ng predictive models at matukoy ang optimum concrete mix design. Ang optimized mixture, na binubuo ng 100% RCA, phosphoric acid treatment, Class C fly ash, at Type G superplasticizer, ay nagkaroon ng predicted compressive strength na 62.88 MPa habang nagpapanatili ng slump na 8 in, kaya natugunan ang target performance criteria. Ipinapakita ng mga resulta ang teknikal na posibilidad ng paggamit ng treated RCA sa paggawa ng kongkreto at nagbibigay ng mahahalagang kaalaman para sa pag-optimize ng RCA-based concrete mixtures para sa praktikal na aplikasyon sa konstruksyon.
Abstract Format
html
Language
English
Format
Electronic
Keywords
Aggregates (Building materials)
Recommended Citation
Eusebio, D. M. (2026). Investigation of treated recycled concrete aggregates for pumpcrete and ready-mix concrete production. Retrieved from https://animorepository.dlsu.edu.ph/etdm_civ/69
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Embargo Period
8-2029
