Key Engineering Materials Vol. 958

Abstract: End-of-life LCD screens from various waste steam have been used to formulate foam glass, aiming for use as light weight, high compressive strength, and insulation purposes. Via conventional ball milling, the foam glass powder was mixed with a binder and fabricated through compaction under 5-10 MPa using stainless steel press moulds to give green samples in cubic and plate shapes. Firing the samples at 1000 – 1050 °C for 0.5-4 hours allowed the construction of foam glass structure, giving low densities of 0.15-0.23 g/cm³. Additions of cordierite, calcium carbonate, graphite and borax determined the phases and composition of the final recycling products. Cristobalite appeared as the main phase along with anorthite were found to give high compressive strength of 1.10-4.22 MPa to the foam glass. The foam glass possessed thermal conductivity in a range of 0.1004-0.1183 W/m K, which can be used for insulation purposes. Different foam glass formulation and geometries required different firing temperature and time to acquire suitable foam glass structure for specific purposes of compressive and thermal insulation properties.

Abstract: To assess the safety and utility of green composite materials as a sustainable structural material, this study investigated their tensile properties using unidirectional jute fiber sliver and poly (lactic acid) and poly (butylene succinate) under loading speed. The fiber volume fraction of the green composite materials was about 10%. Vacuum compression molding was used for molding. Static tensile tests of green composite materials using poly (lactic acid) and poly (butylene succinate) were conducted with 0.1–10 mm/min test speed at room temperature, yielding the following conclusions. Tensile strengths of green composite materials using poly (lactic acid) and poly (butylene succinate) increased with increased test speed. The strain rate dependence of the green composite using poly (lactic acid) became strong, but the strain rate dependence of green composite material using poly (butylene succinate) became weak. Results suggest that the matrix viscoelasticity might influence the loading speed effects on the tensile properties of these green composite materials.

Abstract: Mixed mode (I/II) loading conditions occur frequently in the asphalt layers of pavements. Therefore, a low-temperature fracture analysis based on mixed mode loading turns out to be of utmost importance. In this research, asphalt concrete (AC) mixtures were prepared using two aggregate gradations and PG58-22 bitumen. AC beams were produced by the mixtures and notch offset values of 48 mm, 75.2 mm, and 107.2 mm were fabricated in the beams in order to be tested in a modified single-edge notched beam (SE(B)) setup. The tests were carried out at two temperature levels of-5 °C and-15 °C. Using the modified SE(B) setup and capturing and processing digital imaged from the growing crack during the tests, fracture resistance curves (R-curves) in mixed mode (I/II) conditions could be constructed for each mixture. The results revealed that increasing the mode mixity and impairing the tensile mechanism in the fracture of asphalt beams could significantly contribute to higher fracture resistance of the mixtures. Mixtures with the highest mode mixity exhibited greater crack tip blunting energy by up to 25%. Similarly, energy dissipation in the unstable crack propagation zone is also increased being a desirable characteristic in post-peak performance of the mixtures.

Abstract: The article presents the physical, mechanical (strength, density), and chemicalcharacteristics of complex M100 water-resistant mortar compositions, which include crushedlimestone (0.16–1.25 mm) and granite-crushed sand. Additionally, stone masonry mortar mixtureswith a grain size of up to 5 mm have been developed using local raw materials for the restoration ofwall constructions in building structures.The relationship between the density and chemical stabilityof the hardened samples was determined using the results of complex research on the structuringprocess of the test samples obtained with the modifiers used to improve the workability of theprocessed lime mortars.