PurposeToday, using lightweight structural concrete plays a major role in reducing the damage to concrete structures. On the other hand, lightweight concretes have lower compressive and flexural strengths with lower impact resistance compared to ordinary concretes. The aim of this study is to investigate the effect of simultaneous use of waste glass powder, microsilica and polypropylene fibers to make sustainable lightweight concrete that has high compressive and flexural strengths, ductility and impact resistance.Design/methodology/approachIn this article, the lightweight structural concrete is studied to compensate for the lower strength of lightweight concrete. Also, considering the environmental aspects, microsilica as a partial replacement for cement, waste glass powder instead of some aggregates and polypropylene fibers are used. Microsilica was used at 8, 10 and 12 wt% of cement. Waste glass powder was added to 20, 25 and 30 wt% of aggregates, while fibers were used at 0.5, 1 and 1.5 wt% of cement.FindingsAfter making the experimental specimens, compressive strength, flexural strength and impact resistance tests were performed. Ultimately, it was concluded that the best percentage of used microsilica and glass powder was equal to 10 and 25%, respectively. Furthermore, using 1.5 wt% of fibers could significantly improve the compressive and flexural strengths of lightweight concrete and increase its impact resistance at the same time. For constructing a five-story building, by replacing cement with microsilica by 10 wt%, the amount of used cement is reduced by 5 tons, consequently producing 4,752 kg less CO2 that is a significant value for the environment.Originality/valueThe study provides a basis for making sustainable lightweight concrete with high strength against compressive, flexural and impact loads.

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The environment receives millions of tons of garbage, including plastic and glass, and concrete building debris contributes to a number of environmental problems. In order to reduce cement and make use of waste materials like glass and plastic, this research creates compacted concrete samples using waste glass powder, waste plastic powder, micro-silica, fly ash, and recycled powdered concrete. Compressive, nonlinear behavior, and SEM tests on compacted specimens showed that by removing 80% of the cement and substituting 20% recycled concrete powder, 15% micro-silica, 15% fly ash, 15% waste plastic powder, and 15% waste glass powder (at 80°C for 20 minutes), sustainable concrete with compressive and flexural strengths nearly equal to the sample’s compressive and flexural strengths was produced. Micro-silica has several shortcomings regarding improving concrete strength and building a suitable combination with recycled concrete powder. In extremely small quantities, glass powder may be used to replace cement, and in greater quantities, it can take the place of aggregate. Finally, it was found that concrete mortar could be made completely sustainable by using recycled materials like glass, plastic, and recycled concrete, as well as micro-silica and fly ash, and that only 20% of the weight of cement could be used without lowering the compressive and flexural strength of the concrete.

In this study, the macro‐synthetic polypropylene fibers Forta and Barchip are used. The fibers are added at 0.5%, 1%, 1.5%, and 2% by weight of cement. Additionally, various fiber combinations with varying percentages are employed to create the concrete. Cubic specimens, bending beams, and impact specimens are all prepared on a percentage basis of fiber. The findings indicated that utilizing 1.5% fibrillated Forta fibers raised the compressive strength of the concrete by 18% and the flexural strength of the concrete by 58%. By increasing the usage of Barchip single‐strand fibers by 1.5%, the compressive strength increased by 36%, and the flexural strength increased by 89%. The highest ductility rate refers to the specimen containing 1.5% Forta fiber, with an energy capacity of 672 J. All the hybrid samples also possess a high ductility ratio. Forta fibrillated fibers are more effective in ductility, while Barchip monofilament fiber types can impressively increase the flexural strength of concrete. The hybrid usage of fibers improved compressive strength by 32% and flexural strength by 85%. Additionally, by combining fibers in hybrid form, energy absorption, ductility, impact resistance, and residual flexural strength are increased by 22, 2.3, 3.6, and 5.6 times, respectively, over the control sample.

Epoxy resin is a thermoset polymer and is one of the main candidates for radiation shielding application. In this investigation, carbon, hydrogen, and nitrogen analysis showed that the presence of the light element of nitrogen in cured epoxy could lead to more effective neutron shielding ability compared with physical curing. The effect of neutron irradiation of amine-cured epoxy was studied by infrared spectroscopy. Neat epoxy samples were irradiated at the core of the Tehran Research Reactor in the same neutron flux in the order of 1013 (neutron/cm2×s) at several radiation times (up to 12 h). The results indicated that neutron irradiation caused moderate changes in peak absorption locations of epoxy spectra. This result indicates that, in this neutron flux and irradiation time, the molecular structure of epoxy remains stable.