The construction industry accounts for approximately one-third of the total waste generation globally. With the United Nations projecting a population increase of 2 billion within the next three decades, there is a heightened demand for building stock, generating unprecedented volumes of construction and demolition waste (CDW). To combat this, circular economy strategies are purported to help alleviate the prevailing situation. But a number of challenges are jeopardizing their implementation in the construction industry and preventing from achieving the UN Sustainable Development Goals, net zero carbon and zero avoidable waste targets. This paper systematically analyzes 54 research articles, published in the past decade within major peer-reviewed English-language scholarly publications in the form of a systematic research review. In doing so, it aims to identify and classify the challenges that prevent improved CDW management by assimilating previous research results in support of a circular economy. The classification and analysis using a PESTLE model offers insights into gaps and differences between categories, as well as regions and countries. This initial step could contribute to a better understanding of these barriers, along with associated solutions, which could result in a significant reduction on the impact of construction activities, therefore facilitating the development of an effective circular economy in the sector.

With the rapid pace of global urbanisation, construction demolition waste (CDW) constitutes roughly 36% of the total solid waste deposited in landfill sites worldwide, thereby posing a significant challenge to the sustainability of the construction industry. To address this issue, circular economy strategies are proposed as a solution. This paper systematically analyses 55 research articles published in leading peer-reviewed English-language scholarly journals over the past decade. It aims to identify and categorise drivers for enhanced CDW management by synthesising findings from previous research to support the principles of a circular economy. Utilising a PESTLE model for classification and analysis provides valuable insights into disparities and distinctions among categories, regions, and countries. The resulting analysis yields valuable insights into enablers and trends, with the aim of making a substantial contribution to mitigating the impact of construction activities and thus fostering the establishment of an efficient circular economy within the sector.

The exceeding concrete and washing equipment water are a matter to solve in concrete production. This paper explains several possibilities for recycling and analyses the products obtained with one recycling equipment. The objective of this work is to study the possibility to increase the percentage of recycling in new mixes. The developed study relates wash water density and fine particles content. Besides, mortar and concrete samples were tested introducing different quantities of these fine particles, substituting cement, sand or only as an addition. Consistency, compressive strength, setting time, absorption, and capillarity were tested. The results indicated an improvement of the studied properties in some percentages when substituting sand. It confirms the possibility to introduce larger quantities of wash water in new concrete mixes, with corrections in sand quantity depending on water density.

This paper presents the development of a 3D digital model of end-of-service-life buildings to facilitate a step change in preparation of pre-demolition protocols that can eliminate problems of inadequate documentation and extensive time spent in preparing pre-demolition audits. The 3D digital model consists of the following four main components: (i) digitization of paper-based drawings and their conversion to CAD; (ii) automated generation of a 3D digital model from CAD; (iii) corrections to the 3D digital model to account for changes in the lifetime of a building; (iv) a sub-model for performing pre-demolition audit. This paper proposes the innovative approaches of incorporating a minimal amount of human intervention to overcome numerous difficulties in automated drawing analysis, application of augmented reality (AR) in corrections to the 3D digital model, and data compatibility for pre-demolition audit. These processes are demonstrated using one building as case study. Using the digital model, a pre-demolition audit can be prepared in minutes rather than the many days required in current practice without a digital model. The accurate quantification of the quantities and locations of different demolition waste materials and products in buildings to be demolished will enable a systematic and quantitative evaluation of potentials of material and product reuse and eliminate contamination of different demolition waste streams (which may contain hazardous waste), which is the main cause of environmental degradation and downcycling of demolition waste materials.

The construction industry generates large amounts of waste, usually mixed, which can be composed of different origin materials, most of them catalogued as non-hazardous. The European Union targets for this waste for 2020 have been already achieved by the UK, but it is mainly developed in downcycling processes (backfilling) whereas upcycling (such as recycle in new concrete batches) still keeps at a low percentage. The aim of this paper is to explore further in the use of recycled aggregates from construction and demolition waste (CDW) in concrete mixes so as to improve upcycling. A review of most recent research and legislation applied in the UK is developed regarding the production of concrete blocks. As a case study, initial tests were developed with a CDW recycled aggregate sample from a CDW plant in Swansea. Composition by visual inspection and sieving tests of two samples were developed and compared to original aggregates. More than 70% was formed by soil waste from excavation, and the rest was a mix of waste from mortar, concrete, and ceramics with small traces of plaster, glass and organic matter. Two concrete mixes were made with 80% replacement of recycled aggregates and different water/cement ratio. Tests were carried out for slump, absorption, density and compression strength. The results were compared to a reference sample and showed a substantial reduction of quality in both mixes. Despite that, the discussion brings to identify different aspects to solve, such as heterogeneity or composition, and analyze them for the successful use of these recycled aggregates in the production of concrete blocks. The conclusions obtained can help increase upcycling processes ratio with mixed CDW as recycled aggregates in concrete mixes.