Cleaner Materials最新文献

To address the pressing need for sustainable building materials, this study introduced an innovative and eco-friendly approach to manufacturing thermal-acoustic panels, utilizing agricultural waste with rice straw as the primary material. Paper pulp (PP) and Persea kurzii (PK) were used as non-chemical binders at ratios of 50:50, 60:40, 70:30, and 80:20. After mixing, all the samples were subjected to heat-free hydraulic compression at 5 bars to evaluate their physical, mechanical, thermal, and acoustic properties. Increasing the proportion of the binder directly impacted panel density and flexural strength while also inversely affecting porosity. The PK binder had a low thermal conductivity value of 0.040 W/mK, proving it was a good thermal insulator with a high sound absorption coefficient, especially at higher frequencies. The RSPP-4 panel had the highest noise reduction coefficient (0.51) and absorbed low frequencies, suggesting its potential for noise reduction. Microscopic analysis provided further insight into panel surface characteristics. PP exhibited a smooth surface with a continuous fiber weave that did not obscure the pores, while PK consisted of particles. The correlation between surface characteristics and acoustic performance, especially at high frequencies, underscored the intricate balance between material properties. Research results can be applied in the construction industry to develop sustainable building materials that offer superior thermal and acoustic properties. These thermal-acoustic panels can effectively utilize agricultural waste and show potential as environmentally friendly construction materials to enhance indoor comfort and acoustics in various building environments.

Alternative approaches are urgently needed for both reuse and recycling of poly(vinyl chloride) (PVC) waste. Herein, this study aims to recycle rigid PVC pipe by toughening and plasticizing it with waste cling film (CF). The CF has been first reused as a polymer additive by blending it with PVC from 0 to 50 wt% using a two-roll mill and compression molding machines. Both static and dynamic mechanical properties, morphology, thermal transition, thermal stability, and migration of the recycled PVC (rPVC) were investigated and compared to unmodified rigid PVC. Principal results showed that the CF significantly improved softness and toughness of rPVC. Remarkably increased elongation to 206 % (an 8-fold increase from the rPVC) with strain-hardening event was obtained by utilizing 50 %wt of CF, while tensile and flexural strength decreased owing to the softening effect of CF. There was the strong correlation between microstructure and static mechanical properties. The wire drawing morphology of the toughest rPVC indicated the toughening mechanism of CF via the shear banding behavior, which was inside proposed. A glass transition temperature reduction of 35 ^°C was achieved. Despite the continued migration of plasticizer in the CF modified rPVC, volatilization was diminished across all recycled formulations, leading to comparable thermal stability of the rPVCs with unmodified PVC under typical processing temperatures. According to these findings, the potential capabilities of the CF as the toughening agent and self-plasticizer of PVC for further reutilization were confirmed. This study provides a new idea for reduction of PVC waste and evaluation of their potential applications. An alternative additive, derived from flexible PVC waste, was also explored, and introduced to the polymeric system.

This work examines the environmental impact of low-carbon concrete that incorporates supplementary cementitious materials (SCMs). After reviewing near-zero carbon SCMs and low-carbon concrete, a life cycle assessment (LCA) was undertaken for concrete mix designs with normal-to-high compressive strengths, incorporating limestone and fly ash as cement replacements. The analysis includes relevant region-specific life cycle inventory parameters for raw materials, energy production, and transportation. A comparative assessment between embodied carbon emissions and the material mechanical performance is then made. The results of this paper indicate that incorporating limestone and fly ash in concrete can reduce carbon emissions, yet at a proportional decrease in mechanical properties compared to conventional cement concrete. The combination of cement and fly ash produced, on average, a higher strength concrete by 20.5% and lower CO₂-eq values by 21.1% when compared to limestone cement blends. The CO₂-eq emissions associated with transportation of the main constituents for concrete production were on average below 4% of the total CO₂-eq per mix. In addition to eco-mechanical quantitative assessments, the study offers insights and recommendations for the development of concrete materials considering global resource availability of near-zero carbon concrete constituents.

Dump waste generated by open cast coal mining industry is a significant global source of environmental pollution, land degradation and possesses threats to the environmental sustainability. After conducting pilot study, experimental investigations were conducted to study the reuse of waste rocks coming from mining as fine aggregates as a possible replacement of river sand. Physical, chemical and mechanical tests have been carried out in order to analyze in detail the interaction whether extracted sand is suitable in construction sector or not. The present study focuses on utilizing the overburden of the Sasti open cast coal mine of Western Coal Limited in the Chandrapur District of Maharashtra state, India for extraction of sand. Extracted sand contains minerals mainly quartz, alumina, and satisfies the prescribed permissible limit as per the Indian coal provisions for its use in construction work and observed to be equivalent to river sand. The compressive strength obtained with extracted OB sand after 28 days of curing was 29.294 MPa as compared to 33.153 MPa for the river sand for M25 grade of concrete. The focus of the study is on the reclaimed sand and its possible usages and not on the other components like clay of dump waste.

This study provides new insights in the design of green hybrid polyethylene (PE)-steel fibre reinforced high strength engineered cementitious composite (HSECC) with superior tensile and flexural strength at both ambient and elevated temperatures. Blends of high volume of ground granulated blast furnace slag (GGBFS), dolomite powder and fly ash were utilized to achieve a 60 % cement replacement for the HSECC mixes. These mixes were then exposed to 20–600 °C and a total of 210 specimens were tested to assess their residual tensile stress–strain behaviour, flexural load–displacement response, and toughness. Results indicate that high volume of GGBFS can be very effective in limiting the surface damage and retaining high strength at elevated temperatures. A combination of 1.5 % PE-0.75 % steel with quaternary blend of GGBFS, dolomite and fly ash demonstrated at least 60 % and 40 % retention in tensile and flexural strength at 600 °C, respectively. This was significantly better than the strength of the traditional control silica fume mix considered in this study as well as results reported in many previous literatures on HSECC. Microstructural examination was further conducted to understand the mechanism of fibre deterioration and justify the resulting change in pseudo-hardening behaviour with temperature rise. Findings obtained in this study clearly demonstrated the effectiveness of PE-steel fibre hybridisation at elevated temperature and confirmed that with right binder selection, superior tensile and flexural performance can be achieved even with a very high cement replacement level.

Coffee pulp waste was having potential to be used as a source of non-wood cellulose for papermaking because of its abundance, considerable fraction of cellulose content, and low economic value. In this study, the isolated cellulosic fiber from coffee pulp waste was prepared into paper with the specific purpose of filter for coffee, with the aim as an effort to develop economic value and potential alternative utilization to reduce the environmental impact of coffee pulp waste accumulation, besides suggesting alternative non-wood cellulose source for coffee filter paper. The effect of extraction process repetition using 3 % (w/w) sodium hydroxide was studied to evaluate its effectiveness in removing the non-cellulosic content of coffee pulp, especially lignin, which could damage the taste of coffee. The physical and mechanical properties and water flow ability of coffee pulp filter paper (CPFP) were conducted to evaluate its characteristics and performance. The result showed that three times repetitions of alkali treatment to coffee pulp produced similar lignocellulosic content quality to the commercial wood-based coffee filter paper, with cellulose fraction reaching 86.67 % and residual lignin around 5.39 %. The coffee pulp-based filter paper made from three times repetition of alkali-treated coffee pulp has comparable tensile strength and excellent folding resistance compared to commercial filter paper, which reached around 526 ± 198.4 N/m and 1 df, respectively. The coffee pulp-based filter paper also demonstrated could withstand discharged through by boiling water without breaking. According to the resulting performance of CPFP, coffee pulp waste is promising to be further developed as an alternative non-wood resource for coffee filter paper manufacturing.

The global scientific research circle and government agencies face a number of serious environmental challenges, one of which is the recycling of “End of Life Tires” (ELT). An estimation of one billion tires is expected to end their useful life annually, of which only roughly 50% are recycled at the moment, with the remainder ending up in landfills. Consequently, to solve this gap in the ELT's utilization rate, it is imperative to enhance the current application and furthermore create new applications for recycled tire materials. One of such areas that is currently being investigated is the introduction of waste tire into concrete as partial replacement of natural aggregates in concrete production. Despite its great prospects, it has drawbacks such as lack of proper bonding with the cement matrix and weak rubber intrinsic strength, which make it unsuitable for widespread usage as an aggregate. To get past this obstacle, numerous rubber treatment techniques that enhance the mechanical characteristics of rubber concrete remarkably as well as the bonding properties have been studied by researchers. The impact of rubber percentage replacement, rubber aggregate size and different treatment techniques on various mechanical characteristics of rubber concrete are examined in this review paper. But in order for the concrete industry to embrace it, the researchers need to devise a rubber treatment technique that can tackle the issues of high combustible and the harmful gases that are released from the rubber aggregates when they come in contact with fire.

This study intends to investigate the influence of benzaldehyde and dioctyl phthalate (DOP) on the rheological properties and microstructure of direct coal liquefaction residue (DCLR) modified asphalt binder. The high and low temperature rheological properties and fatigue properties were obtained by dynamic shear rheometer (DSR) and bending beam rheometer (BBR) tests. The scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR) tests were conducted to evaluate the mechanism of property improvement in the DCLR modified asphalt binder. The results showed that the addition of DCLR increased the complex shear modulus G*, rutting factor G*/sin $\delta$ and fatigue life N_f of base asphalt binder, significantly improving the high temperature deformation resistance and fatigue resistance of base asphalt binder. This was attributed to the hardening effect resulting from the addition of DCLR, which enhanced the elastic properties, weakened the viscous properties and fluidity of asphalt binder. Additionally, the use of benzaldehyde and DOP reduced the creep stiffness S and lower continuous grading temperature Tc of DCLR modified asphalt binder, which compensated for the shortcomings of low temperature rheological properties of asphalt binder. The SEM images indicated that benzaldehyde and DOP significantly increased the compatibility of DCLR with the base asphalt binder. The FTIR tests showed that the addition of benzaldehyde and DOP introduced the aldehyde and ester groups, which were interacted with more polar functional groups in the asphalt to reduce the resistance to movement between the heavy components in the DCLR modified asphalt binder, which promoted the flow of asphalt and the dispersion of DCLR, and as a result, the benzaldehyde and DOP modified DCLR asphalt binder exhibited satisfied rheological properties.

Due to rapid population growth and urbanization, construction activities have increased worldwide resulting in generation of enormous volume of construction and demolition (C&D) waste. On one hand, C&D waste is generated during the construction, destruction, and rehabilitation of existing structures. While on the other, the transportation sector consumes large volumes of aggregates for pavement construction and maintenance. The extraction of finite natural aggregates causes potential damage to the environment. Recycled C&D waste, once converted into recycled aggregates, has the potential to be utilized in pavement layers due to its sound quality and composition; also resulting in lowering the landfill loads. This review article critically summarizes the environmental risks regarding chemical composition and leaching behavior of C&D wastes in pavements. Additionally, this review evaluates the environmental impacts of C&D waste aggregate production and application in pavements using life cycle assessment (LCA). Overall, the aim of this study is to investigate the environmental impacts and benefits of C&D waste to enable highway administrations to adopt and promote the use of C&D waste in development of sustainable road infrastructure. In this way, the review article attempts to promote a new era of sustainable road construction and achieve net zero waste goal.

Oil spills represent a critical environmental threat, particularly to marine ecosystems, necessitating the development of efficient and eco-friendly remediation technologies. This study explores the application of pulsed laser ablation (PLA) in fabricating polymer-based magnetic nanocomposites, with a focus on polyvinylpyrrolidone, chitosan, and methyl cellulose. These polymers, renowned for their proficiency in adsorbing pollutants from various oils, were combined with magnetite nanoparticles (NPs) in a compressed tablet form. The PLA process facilitated the generation of nanocomposites, which were subsequently collected using an external magnetic field. The chemical composition of these composites was analyzed through Fourier-transform infrared (FTIR) and Raman spectroscopy, while particle sizes were determined using the Leica Image Processing and Analysis System. The study revealed that PLA is a green, single-step, and effective technique for preparing magnetic nanocomposites, producing particles predominantly in the 400 nm–4 µm size range. Furthermore, the application of these composites in oil/water separation demonstrated with separation commencing approximately 1 s after the application of a magnetic field. These findings underscore the potential of PLA in crafting magnetic nanocomposites for the rapid and environmentally sustainable remediation of oil spills.