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Construction materials are rapidly being used worldwide due to the recent growth in infrastructure and population. Consequently, the natural resources that supply many construction materials, such as natural coarse aggregates, are depleting. This study aims to investigate the use of post-consumer plastic waste with fly ash and bottom ash in the development of synthetic coarse aggregates as a sustainable alternative. Plastic aggregate cubes of various proportions of polyethylene terephthalate (PET) and filler material (fly ash and bottom ash) were cast and tested for 28-day compressive strength. The sample with 40% PET and 60% filler material, of which 20% is fly ash and 80% is bottom ash, produced the highest compressive strength and was chosen as the ideal mix. For each grade of 15, 20, 25, and 30, two sets of concrete cubes were cast with 100% natural aggregates and 100% plastic aggregates. The use of plastic aggregates reduced the compressive strength of concrete. Therefore, with natural and plastic aggregates, two different mixes are required to achieve the same compressive strength. More cement is required with plastic aggregates. Concrete made with plastic aggregates also resulted in substantially lower density and production costs. Consequently, a considerable reduction in the material cost per footing of a sample building was obtained. According to the study, about 1–2 tonnes of gravel per a cubic meter of concrete can be eliminated from construction and reserved in nature altogether. It was apparent that the incorporation of synthetic coarse aggregates using post-consumer PET plastic waste along with fly ash and bottom ash is a sustainable and economically viable alternative to gravel in concrete.

Reactions of BnOm⁺ and BnOmH⁺ clusters (n ≤ 3, m ≤ 4) with D2O have been studied over a collision energy range from 0.1 to 10 eV (center of mass). The reactivity and product branching are found to be highly dependent on the structure of the reactant ion. When available, the preferred site of attack is on a terminal B atom, and the chemistry is dominated by O and OD addition. Even for the most reactive clusters the peak reaction efficiency is only 5−7%, indicating the presence of a bottleneck to reaction. When the reactant has no terminal B atoms, reaction is 1 order of magnitude less efficient and appears to be dominated by attack at nonterminal B atoms. The BnOmH⁺ react similarly, suggesting that the added H atom does not block the reactive sites. This is in contrast to the isoelectronic reaction with HF, where H addition decreased reactivity dramatically. The results are compared with those for related reactions, and with recent ab initio results. In general, theory is consistent with experiment; however, there remain a few problem species.

This paper presents a comprehensive collision-induced dissociation and ab initio study of small boron oxide cations, BnOm⁺, motivated by a need for more accurate and reliable structural and thermodynamic information on both neutral and ionic boron oxides. Absolute fragmentation cross sections were measured for all observable BnOm⁺ (n < 4, m < 5) parent ions at center-of-mass collision energies ranging from 0.08 to 10 eV. Quantitative dissociation thresholds, generated from the experimental data by correcting for the collision energy spread resulting from the beam energy distribution and the thermal motion of the target gas, are compared to ab initio dissociation energies determined from Gaussian-2 calculations.