The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from o...The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from oyster shell farming. However, there is a lack of evidence on the possibility of producing a fully recycled composite consisting of recycled concrete and oyster shell without the need for new cement and natural aggregates. In this study, recycled concrete powder (RCP) and oyster shell were used to produce a green composite. Separate ground and combined ground (separate ground and co-ground) RCP and oyster shells are used to determine the effects of grinding approaches on the mechanical and chemical properties of the composite. The composite samples were molded via press molding by applying 30 MPa of pressure for 10 minutes. The results revealed that the composite prepared via the combined ground approach presented the highest flexural strength compared to the separate ground and unground samples. The FTIR and XRD characterization results revealed no chemical or phase alterations in the raw materials or the resulting composites before and after grinding. SEM analysis revealed that combined grinding reduced the particles’ size and improved the dispersion of the mixture, thereby increasing the strength.展开更多
Natural resource scarcity, CO2 emissions, and solid waste generated from the construction industry are major global environmental and developmental challenges, posing threats to the sustainability of terrestrial and a...Natural resource scarcity, CO2 emissions, and solid waste generated from the construction industry are major global environmental and developmental challenges, posing threats to the sustainability of terrestrial and aquatic ecosystems. In response to this multifaceted issue, recent studies focus on developing non-cement concrete, distinct from traditional cement-based compositions, by utilizing recycled concrete and wood waste molded at high temperature and pressure. Although wood hemicellulose shows adhesive properties and bonds particles at lower temperatures, it has not been studied in non-cement concrete. Hence, the present study focuses on developing green concrete using recycled concrete and hemicellulose, and further enhancing its strength with chitosan. The study used the press molding method with different pressing temperatures. The results, compared with conventional cement mortar and other wood components, revealed that hemicellulose-based green concrete exhibited superior bending strength compared to the other the components and even surpassed the strength of conventional cement mortar. Furthermore, an elevation in temperature to 60˚C resulted in enhanced strength, but a further increase to 160˚C led to delamination and thus a reduction in strength. Moreover, hemicellulose, when substituted by 50% of its weight with chitosan, further enhanced the strength of the concrete. The results also showed that hemicellulose has the potential to produce green concrete from abundant plants in a time interval of no more than ten minutes.展开更多
文摘The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from oyster shell farming. However, there is a lack of evidence on the possibility of producing a fully recycled composite consisting of recycled concrete and oyster shell without the need for new cement and natural aggregates. In this study, recycled concrete powder (RCP) and oyster shell were used to produce a green composite. Separate ground and combined ground (separate ground and co-ground) RCP and oyster shells are used to determine the effects of grinding approaches on the mechanical and chemical properties of the composite. The composite samples were molded via press molding by applying 30 MPa of pressure for 10 minutes. The results revealed that the composite prepared via the combined ground approach presented the highest flexural strength compared to the separate ground and unground samples. The FTIR and XRD characterization results revealed no chemical or phase alterations in the raw materials or the resulting composites before and after grinding. SEM analysis revealed that combined grinding reduced the particles’ size and improved the dispersion of the mixture, thereby increasing the strength.
文摘Natural resource scarcity, CO2 emissions, and solid waste generated from the construction industry are major global environmental and developmental challenges, posing threats to the sustainability of terrestrial and aquatic ecosystems. In response to this multifaceted issue, recent studies focus on developing non-cement concrete, distinct from traditional cement-based compositions, by utilizing recycled concrete and wood waste molded at high temperature and pressure. Although wood hemicellulose shows adhesive properties and bonds particles at lower temperatures, it has not been studied in non-cement concrete. Hence, the present study focuses on developing green concrete using recycled concrete and hemicellulose, and further enhancing its strength with chitosan. The study used the press molding method with different pressing temperatures. The results, compared with conventional cement mortar and other wood components, revealed that hemicellulose-based green concrete exhibited superior bending strength compared to the other the components and even surpassed the strength of conventional cement mortar. Furthermore, an elevation in temperature to 60˚C resulted in enhanced strength, but a further increase to 160˚C led to delamination and thus a reduction in strength. Moreover, hemicellulose, when substituted by 50% of its weight with chitosan, further enhanced the strength of the concrete. The results also showed that hemicellulose has the potential to produce green concrete from abundant plants in a time interval of no more than ten minutes.
