Discarded polyethylene terephthalate (PET) bottles have damaged our ecosystem. Problems of marine fauna conservation and land fertility have been related to the disposal of these materials. Recycled fibre is an opportunity to reduce the levels of waste in the world and increase the mechanical performance of the concrete. PET as concrete reinforcement has demonstrated ductility and post-cracking strength. However, its performance could be optimized. This study considers a statistical-experimental analysis to evaluate recycled PET fibre reinforced concrete with various fibre dose and aspect ratio. 120 samples were experimented under workability, compressive, flexural, and splitting tensile tests. The results pointed out that the fibre dose has more influence on the responses than its fibre aspect ratio, with statistical relation on the tensional toughness, equivalent flexural strength ratio, volumetric weight, and the number of fibres. Moreover, the fibre aspect ratio has a statistical impact on the tensional toughness. In general, the data indicates that the optimal recycled PET fibre reinforced concrete generates a superior performance than control samples, with an improvement similar to those reinforced with virgin fibres.

Harmony search algorithm and its variants have been used in several applications in medicine, telecommunications, computer science, and engineering. This article reviews the global and multi‐objective optimization for chemical engineering using harmony search. The main features of the HS method and several of its popular variants and hybrid versions including their relevant algorithm characteristics are described and discussed. A variety of global and multi‐objective optimization problems from chemical engineering and their resolution using HS‐based methods are also included. These problems involve thermodynamic calculations (phase stability analysis, phase equilibrium calculations, parameter estimation, and azeotrope calculation), heat exchanger design, distillation simulation, life cycle analysis, and water distribution systems, among others. Remarks on future developments of HS and its related algorithms for global and multi‐objective optimization in chemical engineering are also provided in this review. HS is a reliable and promising stochastic optimizer to resolve challenging global and multi‐objective optimization problems for process systems engineering.

Arc concrete structures are aesthetic and suitable for buildings with large spans. Within the framework of this research, fiber-reinforced concrete (FRC) dome-shaped structures were studied in a lab, analyzing mechanical performance via strength, deformation, and failure mode. The studied FRC was elaborated with industrial, recycled, and alternative fibers. The mold used for producing the dome specimens was made up of two parts in order to favor extraction. This study considered 21 dome samples reinforced with fibers and one control, with replication for those with atypical behavior. The results show that the load-displacement behavior of dome-shaped elements increases with the incorporation of fibers, which depends on the fiber dose and the material. Moreover, the efficiency analysis proved that specimens with low fiber content (20 and 2 kg/m3) have the best strength-reinforcement relation. The recycled and alternative fibers exhibit good mechanical performance and ductility. The main contribution of this research is a study of the scope and limitations of different types of FRC as the only reinforcement in arched structures.

Constant loading and transportation of materials cause abrasive wear in industrial floors. This study compared destructive and nondestructive testing techniques to evaluate the abrasion resistance of concrete. Eight concrete hardeners (six solid and two liquid) were subjected to abrasion, ultrasound, and rebound hammer tests. The results of the trials were compared to identify the concrete hardeners that provide more abrasion strength, and also to determine the relationships between the tests. The results indicated that solid hardeners provide more abrasion resistance than liquid ones and that the abrasion, as a destructive test, and the rebound hammer, as a nondestructive test, show similar results.