Amid the COVID-19 pandemic, a sudden surge in the production and utilization of disposable, single-use facial masks has been observed. Delinquency in proposal disposal of used facial masks endangers the environment with a new form of non-biodegradable plastic waste that will take hundreds of years to break down. Therefore, there is an urgent need for the resourceful recycling of such waste in an environmentally friendly way. This study presents an efficient solution by using waste masks in fibered or crushed form to produce environmentally friendly and affordable green concrete. This investigation assessed the mechanical and durability properties of waste masks-incorporated concrete. A total of six mixes were prepared for standardized tests to determine compressive strength, split cylinder tensile strength and rapid chloride penetration test (RCPT), and freeze-thaw resistance. The percentage of mask fibers used were 0.5, 1, 1.5, and 2% of concrete by volume, while crushed masks were used at 0.5% only. The mask waste in both forms was found suitable to be used in concrete. One percent of waste mask fibers was found as an optimum value to increase compressive and tensile strength, reduce chloride permeability, and increase freeze-thaw resistance. Besides this, 0.5% crushed mask fiber also performed well, especially for producing less permeable and highly durable concrete. It is thus corroborated that waste masks that increase pollution worldwide can be utilized sustainably to help build green buildings. By reutilizing waste masks to produce improved concrete with better strengths and higher durability, circular economy and sustainability are achieved, along with efficient waste management.
Concrete used in sewer pipes and industrial areas is susceptible to acid attacks that can significantly damage wastewater infrastructure. This investigation addresses the effect of using both mineral and polymer admixtures on the flowability, compressive strength, and the resistance against sulfuric acid and hydrochloric acid attacks on the modified mortars. The cement was replaced by 10% and 15% of metakaolin along with 5% of two polymer powders: ethylene‐vinyl‐acetate and polyvinyl‐acetate. Raw kaolin clay was heated at 800°C for 8 hours to produce metakaolin. The pozzolanic activity was determined by both strength‐activity index and X‐ray diffraction method. A total of 180 specimens was cast and tested for compressive strength and acid resistance. The outcomes revealed that the workability, along with compressive strength, was improved significantly up to 24% and 18.43%, respectively. While acid resistance of modified mortar was also enhanced considerably by 59.9% and 24.9% against hydrochloric and sulfuric acids, respectively, proving the combinations to be very effective against acid attacks. The investigation focuses on resolving the major wastewater infrastructure issue besides acid utilizing industry and leads toward sustainability. Much sustainable, durable, and environment‐friendly mortar compositions have been suggested to be used in areas prone to acid attacks.
Different types of fibers impart specific characteristics to concrete, including crack bridging, early age crack resistance, ductility, toughness, strength, and loss of workability. It seems that if these fibers are combined, then specific characteristics of each fiber may be imparted to concrete and the desired characteristics of the concrete composite may be achieved. Thus, this investigation has been conducted to study the properties of concrete composites composed of four different types of fibers used singly or in hybrid form. The effectiveness of hybrid fibers in cementitious composites to achieve better characteristics; strengths, toughness, workability, and cost, was investigated and compared. Composites made of carbon fiber, plain steel fiber, polypropylene fiber, and glass fiber and their hybrid combinations (2, 3 and 4 fibers mixed), at constant volume of fiber 1.25%, along 4% styrene-butadiene rubber latex and 1.5% superplasticizer, are prepared and tested. The composites are compared and investigated for their feasibility in terms of their properties and cost. The comparison showed the suitability of some bi-hybrid composites, and incompatibility of tri-hybrid and tetra-hybrid composites in terms of effectiveness and feasibility.
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