Properties of Mortar with Recycled Aggregates, and Polyacrylonitrile Microfibers Synthesized by Electrospinning

Abstract

Currently it is necessary to find alternatives towards a sustainable construction, in order to optimize the management of natural resources. Thus, using recycled fine aggregate (RFA) is a viable recycling option for the production of new cementitious materials. In addition, the use of polymeric microfibers would cause an increase in the properties of these materials. In this work, mortars were studied with 25% of RFA and an addition of polyacrylonitrile PAN microfibers of 0.05% in cement weight. The microfibers were obtained by the electrospinning method, which had an average diameter of 1.024 µm and were separated by means of a homogenizer to be added to the mortar. Cementing materials under study were evaluated for compressive strength, flexural strength, total porosity, effective porosity and capillary absorption, resistance to water penetration, sorptivity and carbonation. The results showed that using 25% of RFA causes decreases mechanical properties and durability, but adding PAN microfibers in 0.05% caused an increase of 2.9% and 30.8% of compressive strength and flexural strength respectively (with respect to the reference sample); a decrease in total porosity of 5.8% and effective porosity of 7.4%; and significant decreases in capillary absorption (approximately 23.3%), resistance to water penetration (25%) and carbonation (14.3% after 28 days of exposure). The results showed that the use of PAN microfibers in recycled mortars allowed it to increase the mechanical properties (because they increase the tensile strength), helped to fill pores or cavities and this causes them to be mortars with greater durability. Therefore, the use of PAN microfibers as a reinforcement in recycled cementitious materials would be a viable option to increase their applications.

The Challenge of Integrating Seismic and Energy Retrofitting of Buildings: An Opportunity for Sustainable Materials?

“…On one hand, this enables reducing the amount of natural resources employed in the construction sector and, on the other, it is an opportunity to find a proper allocation to a by-product that would be otherwise disposed in landfills. Several researchers examined the mechanical performance of concrete and mortar mixtures incorporating such recycled aggregates [97][98][99]. Samiei et al [97] considered an increasing substitution of fine natural aggregates with recycled concrete aggregates in cement and blended cement-lime mortars.…”

Influence of Recycling Processes on Properties of Fine Recycled Concrete Aggregates (FRCA): An Overview

“…Furthermore, the figures presented Fuller's Curve, which represents the grading of aggregate particles resulting in optimum packing, density, and strength of the concrete mixture [92]. [14,35,38,44,46,50,52,59,62]; (b) particle size distributions of FRCAs from CW according to recycling processes [11,16,[23][24][25]28,36,42,43,45].…”

“…Figure 1. (a) Particle size distributions of FRCA from LAB according to recycling processes[14,35,38,44,46,50,52,59,62]; (b) particle size distributions of FRCAs from CW according to recycling processes[11,16,[23][24][25]28,36,42,43,45].…”

Experimental investigation on utilization of substitute building materials in concrete using neural networks

“…This process entails segregating the crushed, demolished concrete waste through sieving to obtain the desired aggregate sizes, followed by conducting various tests to assess aggregate properties before incorporating them into new concrete mixtures [26]. Utilizing construction and demolition waste in this manner has been found to potentially enhance concrete strength by 10-30% [27].…”