Recycling waste materials to produce self-sensing concretes for smart and sustainable structures: A review

Abstract

The construction industry is currently facing the great challenge of applying sustainable materials with suitable mechanical properties and durability performance. Among the different strategies used to meet technical and sustainable criteria, two interesting approaches can be highlighted: the reuse of materials to produce sustainable construction materials and the development of smart concretes for Structural Health Monitoring. The first strategy consists of using recycled materials, co-products, and by-products of industrial processes to replace primary raw materials used to produce blocks, ceramics, mortars, and concrete. The second strategy is associated with the development of multifunctional cementitious and alkali-activated concretes with strain and damage self-sensing properties in response to the growing concerns related to the increase in the durability of civil structures. This paper presents a critical review of previous studies that combine both strategies, i.e., research works investigating smart construction materials that incorporate recycled and waste materials and exhibit self-sensing properties. Sustainable self-sensing composites (SSCs) incorporating different types of recycled and waste materials were presented. These sustainable admixtures provided different benefits to self-sensing composites, such as improvements in the conductive path within the matrices and improvements in the dispersion of other conductive fillers. The effects of silica fume, fly ash, steel slag, red mud, and other recycled materials on the electrical resistivity, strain-sensing properties, and damage-detection properties of SSCs were discussed. Promising SSCs were identified based on comparisons between gauge factor, stress sensibility, linearity, strain amplitude, and stress amplitude of SSCs produced with one single type of waste or combination of various types of wastes. In this sense, SSCs were found to be a viable alternative for modernization and greater sustainability of the construction industry.