RESUMO
Geopolymer materials have been gaining ground in the civil construction sector not only for having superior physical properties when compared to conventional cement, but also for being less harmful to the environment, since the synthesis of the geopolymer does not release toxic gases or require high energy costs. On the other hand, geopolymer materials like cementitious matrices have low flexural strength and have fragile breakage. To overcome these deficiencies, the insertion of fibers in geopolymeric matrices has been evaluated as a solution. Although most research on this practice focuses on the use of synthetic fibers, the use of natural fibers has been growing and brings as an advantage the possibility of producing an even more ecological material, satisfying the need to create eco-friendly materials that exists today in society. Thus, this paper aimed to, through the evaluation of research available in the literature, understand the behavior of fibers in geopolymer matrices, identify similarities and differences between the performance of geopolymer composites reinforced with natural and synthetic fibers and, understanding that it is possible, point out ways to optimize the performance of these composites.
RESUMO
The urbanization process contributes to the growth of solid waste generation and causes an increase in environmental impacts and failures in the management of solid waste. The number of dumps is a concern due to the limited implementation and safe disposal of this waste. The interest in sustainable techniques has been growing in relation to waste management, which is largely absorbed by the civil construction sector. This work aimed to review plastic waste, especially polyethylene terephthalate (PET), that can be incorporated with construction materials, such as concrete, mortars, asphalt mixtures, and paving. The use of life-cycle assessment (LCA) is related, as a tool that allows the sustainability of products and processes to be enhanced in the long term. After analyzing the recent literature, it was identified that studies related to plastic wastes in construction materials concentrate sustainability around the alternative destination of waste. Since the plastic waste from different production chains are obtained, it was possible to affirm the need for a broader assessment, such as the LCA, providing greater quantification of data making the alternative processes and products more sustainable. The study contributes to enhance sustainability in alternative building materials through LCA.
RESUMO
Cementitious materials cause a great impact on the environment due to the calcination of clinker and the extraction of non-renewable mineral resources. In this work, the replacement of quartz sand from the river by PET sand was evaluated at levels of 10%, 20%, and 30%. Tests were performed in the fresh state through consistency, air retention, density, and incorporated air and in the hardened state for compressive strength, flexural strength, density, capillarity, and water absorption. The results show that PET sand is viable in contents of up to 10%, improving the mechanical properties of the mortar and without compromising its workability and incorporated air properties. Above that level, the loss of properties is very excessive, mainly of workability and incorporated air. The incorporated air of the 30% composition, for example, reaches 24%, an excessive value that impacts the properties of the hardened state, making it impossible to use the material at levels greater than 20%. It is concluded that the use of recycled PET sand is a possibility that contributes to sustainable development, as it reduces the extraction of quartz sand from the river, a non-renewable mineral resource.