This study examined the potential of using phase change material (PCM)-integrated concrete slabs for long-term thermal-responsive applications in an outdoor environment condition. The objectives were to: (i) evaluate long-term thermal response, snow melting and freeze–thaw reduction efficiency of PCM integrated concrete slabs, (ii) characterize the chemical stability of PCM in cement matrix, and (ii) assess the possibility of PCM leaching into the cement matrix and subgrade soil of the slabs. The experimental program included: (i) outdoor experimentation using large-scale field concrete slabs, (ii) guarded calorimetric (LGCC) tests of cut-bar concrete specimens, (iii) Fourier transform infrared (FTIR) spectroscopic characterization of PCM in mortar and subgrade soil specimens, and (iv) low-temperature differential scanning calorimetric (LT-DSC) tests to assess and quantify the amount of PCM contamination in subgrade soil. Results presented varying degrees of effectiveness after three years of environmental exposure: Micro-encapsulated PCM (MPCM) concrete exhibited considerable success (i.e., ~ 50%) in snow melting while PCM infused in lightweight aggregates (PCM-LWA) concrete failed to provide substantial snow-melting; moreover, both PCM-LWA and MPCM slabs showed diminished resistance to freeze–thaw (F-T) cycles compared to the first-year winter cycle data. Factors contributing to efficiency loss are found to be shell degradation of microcapsules, potential leaching of PCM into subgrade soil (i.e., between 0.2 to 0.3% wt. concentration), and effects of warm temperatures influencing the degree of evaporation, as evidenced with LGCC, FTIR and LT-DSC results. Strategies to enhance efficiency and stability include improved encapsulation techniques, and vascularization methods.

Improvement of concrete pavements in cold regions is a major issue as durability is impacted by frost action and freeze-thaw cycles. In this study, thermal responsive composites were developed to improve freeze-thaw durability of concrete via incorporation of phase change materials (PCM) using two methods: (i) inclusion of PCM in porous network of lightweight aggregates, and (ii) micro-encapsulated PCM. The experimental program consisted of: (i) evaluation of fresh properties of PCM incorporated concrete mixes, (ii) mechanical and water absorption properties assessment of hardened PCM-concrete mixes, and (iii) assessment of thermal performance of PCM concrete slabs at real-time outdoor and environmental simulated conditions. It was found that the inclusion of micro-encapsulated PCM in concrete during wet mixing forms agglomerates and degrades fresh properties, requiring higher volume fraction of cement paste and superplasticizers to achieve desirable flowability and air entrainment. Incorporation methods have a significant influence on strength and durability factors. An estimation using predictive model showed concrete that has PCM stored in lightweight aggregates as storage agents will take 53.68 ~ 61.45 years until it reaches critical degree of saturation, only if. Thermal assessment results of PCM concrete slabs in outdoor conditions and simulated environmental conditions demonstrated that lightweight aggregate infusion of PCM was more suitable for freeze-thaw resilience concrete infrastructure applications. At outdoor scale, PCM-infused concrete reduced the number of freeze-thaw cycles by an average of 39.62 % in comparison to reference concrete with no PCM during two cold seasons.

This research study examines e-waste management methods and suggests sustainable solutions. Growing e-waste and its hazardous components demand robust management solutions to reduce environmental and health dangers. This report reviews the literature and analyses current processes to summarise e-waste management’s key issues. The article covers policy, regulation, collection and recycling infrastructure, technology, and public awareness. Policies and regulations shape e-waste management. EPR programs, recycling targets, and import/export laws are covered. These policies are assessed to promote responsible e-waste disposal and producer accountability. E-waste collection and recycling require effective infrastructure. Municipal collection facilities, store take-back, and recycling partnerships are compared. E-waste recycling technologies like mechanical and hydrometallurgical processes are evaluated for efficiency, environmental effect, and resource recovery. The study also evaluates how public awareness campaigns promote e-waste disposal. Effective educational, communal, and digital venues for e-waste recycling are assessed. According to the analysis, e-waste management could be improved. Policy frameworks, stakeholder participation, collecting infrastructure, sustainable recycling technologies, and public awareness are improved. This study paper helps policymakers, industry stakeholders, and researchers understand e-waste management systems and find ways to lessen their environmental and health impacts.