Geopolymer, a sustainable alternative to ordinary Portland cement (OPC), offers reduced embodied ... more Geopolymer, a sustainable alternative to ordinary Portland cement (OPC), offers reduced embodied energy, lower carbon emissions, enhanced durability, eco-compatibility, and waste valorization potential. In confining structural members, geopolymer still has limitations with respect to its brittleness and other properties. Enhancing the properties of geopolymer by adding banana fibers (BF) and fly ash (FA) to form banana geotextile-reinforced geopolymer mortar (BGT-RGM) as confining material, is investigated in this experimental study. BGT-RGM is a textile-reinforced mortar with varying thickness of BF-reinforced geopolymer mortar (BFRGM) through NaOH-treated 10 mm BFs and 2 mm banana geotextile (BGT) having varied grid spacings. To develop BGT-RGM, the physical, mechanical, and chemical properties of the BFs were determined, while BFRGMs were evaluated for compressive and dog-bone tensile strengths, workability, scanning electron microscopy (SEM) imaging, and thermogravimetric analys...
Textile reinforced mortar (TRM) are effective method of confining concrete elements to elevate th... more Textile reinforced mortar (TRM) are effective method of confining concrete elements to elevate the axial load resistance and upgrade the overall performance of concrete. TRM is a promising alternative for carbon fiber reinforced polymer (CFRP) which are commonly used in strengthening concrete and are known to be expensive since it requires huge amount of energy in processing these materials. Green technologies can be applied in this process following the same TRM principles of confinement replacing conventional cement or epoxy-based mortar and synthetic textiles towards sustainable concrete strengthening technology. This is through the utilization of geopolymer mortar reinforced with short banana fibers (BF) and long BFs as textiles. Geopolymer mortar presented in this paper is composed of fly ash and silica fume as binder, sand as filler, sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) as activator and BFs as reinforcement and textile. Geopolymerization generates significantly lesser carbon dioxide (CO₂) while BFs are known for having attractive mechanical properties, cost effective and abundant in nature for which making use of its fiber will significantly minimize the huge waste produced from banana plantations after a one-time fruit harvest only. The geotextile or geogrid used to wrap the concrete cylinder samples is made up of 2mm diameter long BF yarns with weights ranging from 150 to 450 grams per square meter that varies with grid sizes from 10mm, 15mm to 25mm for both orthogonal directions considering the lightweight characteristic of BFs. Twelve TRM designs were used to strengthen the concrete cylinders with three samples each. TRM design parameters varies with thickness of geopolymer mortar covering and the size of geotextile grids. Eighteen of the geotextiles used were coated with polymer to protect the fibers while the other eighteen geotextiles remained uncoated. A total of thirty-nine concrete cylinders with 150mm base diameter and 300mm height cured within 28 days were prepared, for which 36 cylinders were confined with green TRM with different parameters while three of the plain concrete cylinders served as control specimens. This is to maximize the investigation on the potential of green TRM in confining concrete and to determine the variations in compressive strengths and mode of failures of confined and unconfined concrete specimens. Results highlighted notable enhancement in the mechanical properties of the modified plain concrete after 28 days of TRM curing using universal testing machine (UTM). Likewise, a confinement theory of the optimum TRM design was modeled mathematically to evaluate the effects of concrete confinement and overall load carrying capacity enhancement gained from additional strength transferred by TRM to the concrete element.
Banana fiber-reinforced geopolymer (BFRG) mortar is an engineered cementitious composite (ECC) th... more Banana fiber-reinforced geopolymer (BFRG) mortar is an engineered cementitious composite (ECC) that can be used in masonry units and repair system of different concrete elements. During geopolymerization, only small amount of carbon dioxide (CO2) is generated and reinforcing it with banana fibers (BFs) made the matrix compact and more earth-friendly. BFs treated with sodium hydroxide (NaOH) enhanced its surface roughness and significantly increased its tensile properties. Design of experiment (DOE) with 13 design mixtures are aimed to obtain the highest value of compressive strength. Factors considered in the DOE are the silica fume (SF) and BF content, ratios of the activator to precursor, water to solids, NaOH to water glass (WG) and fly ash (FA) to sand. The experiment revealed the optimum BFRG mortar and the compatibility of BF to the geopolymer which gained great values for workability, split tensile strength and compressive strength.
From past decades since Joseph Davidovits introduced geopolymer, this innovative green technology... more From past decades since Joseph Davidovits introduced geopolymer, this innovative green technology as alternative for cement mortar have been studied and proven its strength, effectiveness, and potential to many applications. Likewise, crack proneness due to lack of reinforcement, occurrence of efflorescence and curing methods are issues on geopolymer. This paper focused on the effects of treated banana fibres (BF) using 4 % sodium hydroxide (NaOH) soaked within 2, 4 and 6 h which served as reinforcement on the geopolymer mortar with different parameters to eliminate macro cracks and two curing methods were used to address efflorescence. Fiber reinforced geopolymer mortar (FRGM) can lessen the massive utilization of conventional construction materials due to sustainability of geopolymer and provide crack bridging in the matrix. Compressive and split tensile strength test of geopolymer cube and cylinder samples for burlap and saran wrapped method of ambient curing were determined using universal testing machine (UTM). The flowability, weight loss of samples during curing period and the occurrence of efflorescence were observed as well. In Design Mixture - 1 (DM1), there are 13-design mixtures (DM) with 5 - 50x50x50 mm cubes and 5 -100x200 mm cylinder specimens each reinforced with BF while 8 DMs for DM1 are plain geopolymer mortar (PGM) to obtain the mixture with the highest compressive and split tensile strength for both FRGM and PGM. FRGM and PGM with the highest mechanical strength are further explored reinforcing with treated and untreated BFs. Mechanical strengths, flowability, efflorescence and weight loss of samples were recorded. The optimum FRGM shows that there is no significant difference in compressive and split tensile strength when reinforced with 4 % NaOH treated within 2 and 6 h compared to 4 h of treatment which has the highest strengths. Finally, the governing BF with 4 % NAOH treated within 4 h was used to reinforce the PGM to investigate the strength variation provided by BFs which gave up to 22.43 % increment in terms of compressive strength.
The Philippine's Heritage Province of Ilocos is a place where most of the old and historical buil... more The Philippine's Heritage Province of Ilocos is a place where most of the old and historical buildings are located particularly at Vigan City. This city is one of the New Seven Wonder Cities of the World (N7WC) because of its well-preserved old structures including school buildings which were built almost a century ago. Amongst these old structures, the reinforced concrete school building located at Vigan situated near the famous Heritage Village's Calle Crisologo was chosen for the case study. This school building was partially damaged during the M7.8 1990 Great Luzon Earthquake; the second most powerful but most disastrous earthquake ever recorded in the country. The building was retrofitted using section enlargement on frontal columns and its foundations only after the earthquake. This study aims to increase the seismic resistance of the structure and preserve the retrofitted building damaged by the 1990 earthquake due to structural weakening which includes cracks, corrosion and strength deficiencies 29 years after it was retrofitted. This study will also serve as a benchmark for other weak buildings and will promote structural retrofitting and Non-destructive Testing (NDT) in the province. While the City and the Province is on its face lifting for safer and more resilient school buildings it is deemed necessary to study and establish the application of different state of the art retrofitting methods being adapted worldwide to school buildings. Retrofitting methods used in the study include Carbon Fiber Reinforced Polymer (CFRP), RC Jacketing, and steel jacketing. NDT equipment from a Well-built Specialty Contractor was used on the structural investigation and assessment of the building to avoid the stressful effect of traditional destructive testing. NDT equipment includes the rebound hammer for concrete compressive strength, ultrasonic pulse velocity test (UPV) to establish homogeneity of concrete and rebar locator for reinforcement mapping. ETABS and MIDAS structural software were utilized for structural analysis and detailing. The selection of retrofitting methods is based on structural strength, economy, and space considerations. From the analysis, the existing retrofitted columns are still capable of resisting axial and lateral loads generated from structural software. On the other hand, interior columns, beams and slabs are required to be retrofitted using CFRP which passed the design requirements and saves building spaces. The rear exterior columns must have section enlargement due to some exposed reinforcement which had caused cracks and corrosion to be treated first before retrofitting structural elements. Maintenance and repair were recommended for non-structural members and all foundations except at the front row shall be retrofitted using section enlarge to satisfy the most recent design code requirements.
Geopolymer, a sustainable alternative to ordinary Portland cement (OPC), offers reduced embodied ... more Geopolymer, a sustainable alternative to ordinary Portland cement (OPC), offers reduced embodied energy, lower carbon emissions, enhanced durability, eco-compatibility, and waste valorization potential. In confining structural members, geopolymer still has limitations with respect to its brittleness and other properties. Enhancing the properties of geopolymer by adding banana fibers (BF) and fly ash (FA) to form banana geotextile-reinforced geopolymer mortar (BGT-RGM) as confining material, is investigated in this experimental study. BGT-RGM is a textile-reinforced mortar with varying thickness of BF-reinforced geopolymer mortar (BFRGM) through NaOH-treated 10 mm BFs and 2 mm banana geotextile (BGT) having varied grid spacings. To develop BGT-RGM, the physical, mechanical, and chemical properties of the BFs were determined, while BFRGMs were evaluated for compressive and dog-bone tensile strengths, workability, scanning electron microscopy (SEM) imaging, and thermogravimetric analys...
Textile reinforced mortar (TRM) are effective method of confining concrete elements to elevate th... more Textile reinforced mortar (TRM) are effective method of confining concrete elements to elevate the axial load resistance and upgrade the overall performance of concrete. TRM is a promising alternative for carbon fiber reinforced polymer (CFRP) which are commonly used in strengthening concrete and are known to be expensive since it requires huge amount of energy in processing these materials. Green technologies can be applied in this process following the same TRM principles of confinement replacing conventional cement or epoxy-based mortar and synthetic textiles towards sustainable concrete strengthening technology. This is through the utilization of geopolymer mortar reinforced with short banana fibers (BF) and long BFs as textiles. Geopolymer mortar presented in this paper is composed of fly ash and silica fume as binder, sand as filler, sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) as activator and BFs as reinforcement and textile. Geopolymerization generates significantly lesser carbon dioxide (CO₂) while BFs are known for having attractive mechanical properties, cost effective and abundant in nature for which making use of its fiber will significantly minimize the huge waste produced from banana plantations after a one-time fruit harvest only. The geotextile or geogrid used to wrap the concrete cylinder samples is made up of 2mm diameter long BF yarns with weights ranging from 150 to 450 grams per square meter that varies with grid sizes from 10mm, 15mm to 25mm for both orthogonal directions considering the lightweight characteristic of BFs. Twelve TRM designs were used to strengthen the concrete cylinders with three samples each. TRM design parameters varies with thickness of geopolymer mortar covering and the size of geotextile grids. Eighteen of the geotextiles used were coated with polymer to protect the fibers while the other eighteen geotextiles remained uncoated. A total of thirty-nine concrete cylinders with 150mm base diameter and 300mm height cured within 28 days were prepared, for which 36 cylinders were confined with green TRM with different parameters while three of the plain concrete cylinders served as control specimens. This is to maximize the investigation on the potential of green TRM in confining concrete and to determine the variations in compressive strengths and mode of failures of confined and unconfined concrete specimens. Results highlighted notable enhancement in the mechanical properties of the modified plain concrete after 28 days of TRM curing using universal testing machine (UTM). Likewise, a confinement theory of the optimum TRM design was modeled mathematically to evaluate the effects of concrete confinement and overall load carrying capacity enhancement gained from additional strength transferred by TRM to the concrete element.
Banana fiber-reinforced geopolymer (BFRG) mortar is an engineered cementitious composite (ECC) th... more Banana fiber-reinforced geopolymer (BFRG) mortar is an engineered cementitious composite (ECC) that can be used in masonry units and repair system of different concrete elements. During geopolymerization, only small amount of carbon dioxide (CO2) is generated and reinforcing it with banana fibers (BFs) made the matrix compact and more earth-friendly. BFs treated with sodium hydroxide (NaOH) enhanced its surface roughness and significantly increased its tensile properties. Design of experiment (DOE) with 13 design mixtures are aimed to obtain the highest value of compressive strength. Factors considered in the DOE are the silica fume (SF) and BF content, ratios of the activator to precursor, water to solids, NaOH to water glass (WG) and fly ash (FA) to sand. The experiment revealed the optimum BFRG mortar and the compatibility of BF to the geopolymer which gained great values for workability, split tensile strength and compressive strength.
From past decades since Joseph Davidovits introduced geopolymer, this innovative green technology... more From past decades since Joseph Davidovits introduced geopolymer, this innovative green technology as alternative for cement mortar have been studied and proven its strength, effectiveness, and potential to many applications. Likewise, crack proneness due to lack of reinforcement, occurrence of efflorescence and curing methods are issues on geopolymer. This paper focused on the effects of treated banana fibres (BF) using 4 % sodium hydroxide (NaOH) soaked within 2, 4 and 6 h which served as reinforcement on the geopolymer mortar with different parameters to eliminate macro cracks and two curing methods were used to address efflorescence. Fiber reinforced geopolymer mortar (FRGM) can lessen the massive utilization of conventional construction materials due to sustainability of geopolymer and provide crack bridging in the matrix. Compressive and split tensile strength test of geopolymer cube and cylinder samples for burlap and saran wrapped method of ambient curing were determined using universal testing machine (UTM). The flowability, weight loss of samples during curing period and the occurrence of efflorescence were observed as well. In Design Mixture - 1 (DM1), there are 13-design mixtures (DM) with 5 - 50x50x50 mm cubes and 5 -100x200 mm cylinder specimens each reinforced with BF while 8 DMs for DM1 are plain geopolymer mortar (PGM) to obtain the mixture with the highest compressive and split tensile strength for both FRGM and PGM. FRGM and PGM with the highest mechanical strength are further explored reinforcing with treated and untreated BFs. Mechanical strengths, flowability, efflorescence and weight loss of samples were recorded. The optimum FRGM shows that there is no significant difference in compressive and split tensile strength when reinforced with 4 % NaOH treated within 2 and 6 h compared to 4 h of treatment which has the highest strengths. Finally, the governing BF with 4 % NAOH treated within 4 h was used to reinforce the PGM to investigate the strength variation provided by BFs which gave up to 22.43 % increment in terms of compressive strength.
The Philippine's Heritage Province of Ilocos is a place where most of the old and historical buil... more The Philippine's Heritage Province of Ilocos is a place where most of the old and historical buildings are located particularly at Vigan City. This city is one of the New Seven Wonder Cities of the World (N7WC) because of its well-preserved old structures including school buildings which were built almost a century ago. Amongst these old structures, the reinforced concrete school building located at Vigan situated near the famous Heritage Village's Calle Crisologo was chosen for the case study. This school building was partially damaged during the M7.8 1990 Great Luzon Earthquake; the second most powerful but most disastrous earthquake ever recorded in the country. The building was retrofitted using section enlargement on frontal columns and its foundations only after the earthquake. This study aims to increase the seismic resistance of the structure and preserve the retrofitted building damaged by the 1990 earthquake due to structural weakening which includes cracks, corrosion and strength deficiencies 29 years after it was retrofitted. This study will also serve as a benchmark for other weak buildings and will promote structural retrofitting and Non-destructive Testing (NDT) in the province. While the City and the Province is on its face lifting for safer and more resilient school buildings it is deemed necessary to study and establish the application of different state of the art retrofitting methods being adapted worldwide to school buildings. Retrofitting methods used in the study include Carbon Fiber Reinforced Polymer (CFRP), RC Jacketing, and steel jacketing. NDT equipment from a Well-built Specialty Contractor was used on the structural investigation and assessment of the building to avoid the stressful effect of traditional destructive testing. NDT equipment includes the rebound hammer for concrete compressive strength, ultrasonic pulse velocity test (UPV) to establish homogeneity of concrete and rebar locator for reinforcement mapping. ETABS and MIDAS structural software were utilized for structural analysis and detailing. The selection of retrofitting methods is based on structural strength, economy, and space considerations. From the analysis, the existing retrofitted columns are still capable of resisting axial and lateral loads generated from structural software. On the other hand, interior columns, beams and slabs are required to be retrofitted using CFRP which passed the design requirements and saves building spaces. The rear exterior columns must have section enlargement due to some exposed reinforcement which had caused cracks and corrosion to be treated first before retrofitting structural elements. Maintenance and repair were recommended for non-structural members and all foundations except at the front row shall be retrofitted using section enlarge to satisfy the most recent design code requirements.
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