The difficult current environmental situation, caused by construction industry residues containing ceramic materials, could be improved by using these materials as recycled aggregates in mortars, with their processing causing a reduction in their use in landfill, contributing to recycling and also minimizing the consumption of virgin materials. Although some research is currently being carried out into recycled mortars, little is known about their stress-strain (σ-ε); therefore, this work will provide the experimental results obtained from recycled mortars with recycled ceramic aggregates (with contents of 0%, 10%, 20%, 30%, 50% and 100%), such as the density and compression strength, as well as the σ-ε curves representative of their behavior. The values obtained from the analytical process of the results in order to finally obtain, through numerical analysis, the equations to predict their behavior (related to their recycled content) are those of: σ (elastic ranges and failure maximum), ε (elastic ranges and failure maximum), and Resilience and Toughness. At the end of the investigation, it is established that mortars with recycled ceramic aggregate contents of up to 20% could be assimilated just like mortars with the usual aggregates, and the obtained prediction equations could be used in cases of similar applications.

In the field of construction, sustainable building materials are currently undergoing a process of technological development. This study aims to contribute to understanding the behavior of the fundamental properties of concretes prepared with recycled coarse aggregates that incorporate a polyethylene terephthalate (PET)-based additive in their matrix (produced by synthesis and glycolysis of recycled PET bottles) in an attempt to reduce their high porosity. Techniques to measure the gas adsorption, water porosity, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to evaluate the effect of the additive on the physical, mechanical and microstructural properties of these concretes. Porosity reductions of up to 30.60% are achieved with the addition of 1%, 3%, 4%, 5%, 7% and 9% of the additive, defining a new state in the behavioral model of the additive (the overdosage point) in the concrete matrix; in addition, the porous network of these concretes and their correlation with other physical and mechanical properties are also explained.

Due to the current problems related to the generation of diverse wastes and the extraction of nonrenewable materials to be used in the construction sector, the alternative use of waste glass could be a sustainable option with environmental and economic benefits, in case of being feasible its use as a replacement of the usual aggregates to manufacture recycled mortars. In this research, one presents a study of the fresh-state properties of the mortars containing 15, 30, 60, and 100% recycled glass aggregates as a replacement for the usual aggregate, providing the experimental results of consistency, density, and air content. Using the experimental results, and by means of a numerical and statistical analysis of these, a diagram of triple interaction that allows us to unify the behavior of the studied properties is constituted; making feasible with this, the prediction of the behavior of these properties with respect to variables as their ratio water/cement, aggregate/cement, and different percentages of replacement of aggregates.

Abstract

Revista de la Construcción Journal of Construction 22] Mechanical properties of mortars containing recycled ceramic as a fine aggregate replacement Propiedades mecánicas de morteros que contienen cerámica reciclada como reemplazo del árido fino Abstract We study the behavior of mortars where 0%, 10%, 20%, 30%, 50% and 100% of their original natural sand was replaced by ceramic sand in a search of potential new building materials that will help to conserve natural resources and that are environmentally friendly. In this paper, the physical properties of the sands and their derived mortars, including their compressive strength, flexural strength, and shrinkage due to base and total drying, are characterized. Our results show that the compressive and flexural strengths of the recycled mortars decrease proportionally to the amount of natural sand replacement used. A similar behavior is observed for the shrinkage due to drying in mortars with low ceramic substitutions (10%, 20% and 30%). Based on these findings, we believe that the use of mortars made with recycled sand (with substitution contents lower than 30%) could be feasible in applications where the mechanical requirements are low. Resumen A partir de la búsqueda de nuevas alternativas en el área de construcción que ayuden a la conservación de los recursos naturales y del medio ambiente, se estudia el comportamiento de morteros con sustituciones parciales de reemplazo del 0%, 10%, 20%, 30%, 50% y 100% de arena cerámica reciclada por arena natural. Se caracterizan las propiedades físicas de las arenas estudiadas, así como las propiedades mecánicas de los morteros resultantes de ellas; tales como la resistencia a la compresión, flexión y de retracción básica, por secado y total. Los resultados obtenidos indican que para la resistencia a compresión y a flexión de los morteros reciclados, éstos sufren decrementos proporcionales al remplazo de la arena natural; sin embargo, para el caso de la retracción por secado éstos reportan comportamiento similar (morteros con sustituciones bajas de 10%, 20% y 30%). En base a lo anterior, morteros con arena cerámica reciclada (con contenidos menores al 30% de reemplazo) podrían ser factibles de su utilización en aplicaciones, en las cuales los requerimientos de éstos sean bajos.