Recycling paper sludge waste (PSW) into inexpensive sheets for applications in household interiors, construction, and footwear is a sustainable approach to resource utilisation and pollution reduction. A flexible recycled sheet (FRS) in board form was developed using cellulosic-based PSW from the paper industry and a styrene-butadiene rubber (SBR) binder. Various SBR concentrations were tested to determine the optimal amount for superior mechanical properties. The produced FRS was characterised using Fourier transform infrared spectroscopy, thermogravimetric analysis, high-resolution scanning electron microscopy, and energy-dispersive X-ray spectroscopy. FRS made with 1000 g of PSW:300 ml of SBR exhibited enhanced mechanical properties, including tensile strength (62.32 +/- 0.51 MPa), elongation at break (51.99 +/- 0.94%), tearing strength (17.76 +/- 0.45 N/mm), and flexibility (6.98 +/- 0.24%). A biodegradation study, conducted per ASTM D 5988-03, assessed environmental impact by measuring carbon-to-CO2 conversion in soil over 90 days. All FRS samples showed similar degradation within the first 30 days, with FRS 5 degrading significantly faster thereafter due to its higher cellulose and hemicellulose content. This highlights the potential of PSW-based FRS as an environmentally friendly and mechanically robust material for diverse applications.

In this study, a green and cost-effective cement system was developed with bagasse ash (BA incorporating limestone calcined clay cement (LC3) as ordinary Portland cement (OPC) replacement from black cotton soil (BCS) stabilisation perspective. Effect of BA incorporating 20 % - 60 % range of LC3 on standard consistency (SC), setting time (ST) and compressive strength properties was investigated and optimised through comparison studies with similar properties to BA incorporating 20 % - 60 % range of OPC. Optimum content of BA incorporating LC3 was added to BCS in different mix proportion range of 0-18 %. Effect of addition of different content of BA incorporating LC3 on performance of BCS specimens was examined in terms of compaction, free swell and durability properties. The results show that utilisation of BA incorporating LC3 maintains compressive strength and improves SC as well as ST of BA incorporating LC3 paste. Compared to BA incorporating OPC, BA incorporating 40 % of LC3 content at 0.50 water-cement (w/c) ratio obtained a good comprehensive strength equivalent cement performance. From the experimental results, it was found that addition of BA incorporating LC3 at optimal content significantly improved compaction, swell potential and durability properties of treated BCS. This study demonstrates technical feasibility of BA incorporating LC3 as a cement replacement. It verifies the reuse of by-products from agriculture for application as cementitious materials. The study further promotes the utilisation of BA incorporating LC3 for addressing climate change emergency and reducing high costs for routine BCS stabilisation practice.

Civil and geotechnical researchers are searching for economical alternatives to replace traditional soil stabilizers such as cement, which have negative impacts on the environment. Chitosan biopolymer has shown its capacity to efficiently minimize soil erosion, reduce hydraulic conductivity, and adsorb heavy metals in soil that is contaminated. This research used unconfined compression strength (UCS) to investigate the impact of chitosan content, long-term strength assessment, acid concentration, and temperature on the improvement of soil strength. Static triaxial testing was employed to evaluate the shear strength of the treated soil. Overall, the goal was to identify the optimum values for the mentioned variables so that the highest potential for chitosan-treated soil can be obtained and applied in future research as well as large-scale applications in geotechnical engineering. The UCS results show that chitosan increased soil strength over time and at high temperatures. Depending on the soil type, a curing temperature between 45 to 65 degrees C can be considered optimal. Chitosan biopolymer is not soluble in water, and an acid solution is needed to dissolve the biopolymer. Different ranges of acid solution were investigated to find the appropriate amount. The strength of the treated soil increased when the acid concentration reached its optimal level, which is 0.5-1%. A detailed chemical model was developed to express how acid concentration and temperature affect the properties of the biopolymer-treated soil. The SEM examination findings demonstrate that chitosan efficiently covered the soil particles and filled the void spaces. The soil was strengthened by the formation of hydrogen bonds and electrostatic interactions with the soil particles.

The materials traditionally used in the construction of flexible and rigid pavements in modern road infrastructure present challenges in achieving sustainable development goals. Advances in technology have introduced the use of different pavement material mixes, leading to the introduction of earth-based alternatives. These materials are environmentally friendly, cost-effective, recyclable, and offer excellent insulation properties. Stabilization of earth-based materials improves their mechanical properties, reducing road construction costs and increasing durability. The present study investigates the mechanical and durability properties of earth-based materials stabilized with various additives, including cement, lime, polymer, and biopolymer, over 28 and 56 days. Fresh properties are assessed using unit volume weight, flow table, air content, and fall cone tests, while hardened properties are assessed using flexural strength, compressive strength, and water absorption. Microstructural analysis is carried out using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The cement-stabilized samples show improved strength and durability, with the 5% cement group showing a 67% increase in compressive strength over the control group and the 10% cement group showing over 200% higher compressive strength. These results suggest that stabilized earth-based materials could provide a cost-effective and sustainable alternative to conventional pavements for low-traffic roads.

This study presents a novel approach to determining the soil's elastic modulus (E'), a critical parameter in geotechnical engineering, by employing derivative-based methodologies and one-dimensional consolidation test results. The main challenges of traditional methods, such as triaxial CD testing, include high costs, long duration, and complexity in data collection and analysis. This new approach addresses these challenges by applying derivative calculations at a specific reference stress point (Pref), resulting in a tangent equation that accurately represents the soil's compressive behavior. Utilizing the results from one-dimensional consolidation tests not only reduces dependence on costly triaxial CD tests but also ensures high accuracy in evaluating soil mechanical properties. The findings indicate that the E' value obtained from this new method is equivalent to that from triaxial CD tests, confirming the method's feasibility and effectiveness. The unique achievement of this research is the development of a fast, cost-effective, and efficient method for determining the soil's elastic modulus, opening new research directions in the field of geotechnical engineering.

In addition to causing domestic and regional environmental effects, many air pollutants contribute to radiative forcing (RF) of the climate system. However, climate effects are not considered when cost-effective abatement targets for these pollutants are established, nor are they included in cur-rent international climate agreements. We construct air pollution abatement scenarios in 2030 which target cost-effective reductions in RF in the EU, USA, and China and compare these to abatement scenarios which instead target regional ozone effects and particulate matter concentrations, Our analysis covers emissions of PM (fine, black carbon and organic carbon), SO2, NOx, CH4, VOCs, and CO. We find that the effect synergies are strong for PM/BC, VOC, CO and CH4. While an air quality strategy targeted at reducing ozone will also reduce RF, this will not be the case for a strategy targeting particulate matter. Abatement in China dominates RF reduction, but there are cheap abatement options also available in the EU and USA. The justification for international cooperation on air quality issues is underlined when the co-benefits of reduced RF are considered. Some species, most importantly SO2, contribute a negative forcing on climate. We suggest that given current knowledge, NOx and SO2 should be ignored in RF-targeted abatement policies. (C) 2009 Elsevier Ltd. All rights reserved.