Exploring environmental and economic costs and benefits of a circular economy approach to the construction and demolition sector. A literature review

Status quo and future directions of construction and demolition waste research: A critical review

Construction and demolition wastes (C&DW) are usually recognized as not dangerous, but their accumulation can generate serious environmental problems. In spite of C&DW high potential to be reused/recycled, the practical procedures need to be assessed in terms of environmental consequences. The objective of this study is to quantify the environmental impacts of C&DW recycling/reuse, specifically in the production of aggregate 0/30 mm, comparative to those generated during the natural inert processing, in terms of global impacts addressing the whole process and for each technological phase. The analysis was carried out using Life Cycle Assessment methodology, assisted by SimaPro software, and based on primary data collected directly from the Italian Emilia Romagna region. Three methods were used for impact quantification: Eco-Indicator 99, EDIP/UMIP and Cumulative Energy Demand. The analysis revealed that the environmental impacts generated by C&DW recycling/reuse accounting for about 40% of the imp...

Comparing environmental impacts of natural inert and recycled construction and demolition waste processing using LCA

Significant efforts have been devoted to assessing construction and demolition waste management (CDWM). However, there is little knowledge to understand the utilisation of the developed models for assessing CDWM performance, thus limiting the comparison and generalization of recognized methods and tools. By reviewing the prior published literature, this study assesses the current research methods, in particular, data collection. It also reviews the range of critical indicators for CDWM performance assessment considered by the literature and put forwards a new framework for better assessing CDWM performance. The proposed framework summarises the system boundary, research scale and performance assessment aspects documented by previous studies, and further integrate an integrated framework with procedures for better assessing CDWM performance. The literature review found that while some studies adopt a system thinking and life cycle thinking to assess CDWM performance, other research they adopt a sustainability based model to finalize CDWM performance assessment. The results also demonstrate that compared with environmental and economic aspects, the social aspect has attracted less attention. Social factors, however are crucial in CDWM. The findings about current performance assessment practices in CDWM and the proposed procedures are possible to implement for researchers and practitioners to develop sound CDWM approaches.

A review of performance assessment methods for construction and demolition waste management

Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation-biostimulation approach coupled with rye cultivation had the most profound effect on TNT degradation. Although plants enhanced the total microbial community abundance, blue fenugreek cultivation did not significantly affect the TNT degradation rate. The results from molecular analyses suggested the survival and...

Microbial community changes in TNT spiked soil bioremediation trial using biostimulation, phytoremediation and bioaugmentation

Construction and demolition waste (C&DW) are the result of inefficient and unsustainable use of natural resources and energy in production processes and other human activities, leading to economic losses. In this paper, the Ecological Footprint (EF), as a new indicator and methodology in environmental sustainability assessment was used to calculate where and how the humans induce impacts on the environment, in particular due to the generation of C&DW. Ecological footprint makes a relationship between two factors the amount of land required to dispose per capita generated waste. The study proposes the calculation of EF to develop a sustainable C&DW integrated waste management in European countries, considering the methodologies developed for solid waste management. For the development of the proposed analysis, four C&DW management scenarios were proposed based on the actual situation of C&DW in 2009, in Iasi, Romania and Bologna, Italy. The evaluation is based on Life Cycle Assessment (LCA) methodology, assisted by SimaPro software that calculates the EF using indicators like CO2, land use and nuclear footprints. The research showed that the EF could be used as an indicator able to evaluate the sustainability of C&DW integrated management systems in various countries and locations, being recommended as a decision making support tool..

Ecological footprint applied in the assessment of construction and demolition waste integrated management

The properties of fibre-reinforced polymer (FRP) composites have led to a significant increase of civil engineering applications based on the usage of these materials. In the construction sector, FRP are mainly used for strengthening existing buildings, thus creating the possibility of avoiding the environmental problems resulting from demolishing these structures and constructing new ones. In the light of this new opportunity, the present paper aims at evaluating and comparing the environmental performances of an unstrengthened reinforced concrete (RC) beam with those of different carbon fibre-reinforced polymer (CFRP) flexural strengthening techniques. The paper uses Life Cycle Assessment (LCA) methodology in order to determine the most environmentally friendly solution in the case of an existing RC beam which does not properly satisfy the structural demands. The authors have decided to use the Cradle-to-Gate LCA type of study, considering that the primary goal of the paper is to establish whether strengthening and reusing an existing RC beam can be considered a more viable environmentally friendly proposal in contrast with demolishing the existing structural element and constructing a new one. The following impact categories are used with the purpose of achieving a clear understanding of the products’ environmental influence: Climate Change, Human Toxicity, and Ozone Depletion. Their environmental performances are evaluated using the GaBi 6 software. The obtained results show that all the assessed CFRP strengthening solutions have a significantly lower environmental impact in comparison with those of the RC beam. In the case of the analysed RC structural element, the highest impact is attributed to the manufacturing stage of the cement and to the steel reinforcements. In most of the CFRP strengthening schemes, the environmental impact is mainly influenced by the amount of component materials (fibre and resin) used for manufacturing the considered composite elements. The resulted values for the environmental parameters in the assessed case studies encourage the authors to assert that the usage of composite materials in specific civil engineering applications can represent an environmentally friendly solution. The environmental aspect of sustainability can thus be achieved in this industry by using particular FRP strengthening applications. Moreover, the negative effects of modern society over Earth can be reduced. The paper concludes that the usage of composite materials can represent an important step towards the sustainable development of the construction sector.

Environmental impact of carbon fibre-reinforced polymer flexural strengthening solutions of reinforced concrete beams

The current consumption rates and the overall impact of humankind over the Earth’s ecosystem will reach a critical level, placing future generations into a perilous limit to evolution. Therefore, in the coming years, improving the state of the natural environment will represent a vital challenge for society. One of the most important tasks in achieving this global goal is represented by satisfying the primary aspects of sustainability in the construction sector. Thus, the present chapter analyzes the implications, with respect to the environmental dimension of sustainable development, from considering different carbon fiber-reinforced polymers for strengthening reinforced concrete (RC) beams. The main scope of the conducted life cycle assessment studies is to determine if composite materials should be considered in minimizing the environmental footprint of the built environment, by determining the most suitable solution: strengthening and reusing, or demolishing and building a new RC beam.

Life cycle analysis of strengthening concrete beams with FRP

The road infrastructure has a major environmental impact by covering important land surfaces and consuming enormous amounts of raw materials for construction and maintenance. The impact of transport pavements needs to be considered from the design stage and to be examined during the whole life cycle of the infrastructure: raw materials extraction and initial transformation, manufacturing, placement on site, exploitation, maintenance, and demolition. This paper evaluates the impact of asphalt and concrete pavements. Two specific case studies, both involving alternatives available for the construction of pavements, namely the conventional flexible pavement designed according to national standard versus the modern steel fibre-reinforced roller-compacted concrete (SFR-RCC) pavement have been undertaken. These alternatives have been analysed, using the GaBi software, to assess their environmental aspects relating to the sustainability concept. After a detailed discussion of the main results obtained in these studies, conclusions and recommendations for an efficient selection of the construction alternatives are formulated.

Sebastian George Maxineasa

Papers

Ecological footprint applied in the assessment of construction and demolition waste integrated management

Environmental impact of carbon fibre-reinforced polymer flexural strengthening solutions of reinforced concrete beams

Life cycle analysis of strengthening concrete beams with FRP

Evaluation of the environmental impact of road pavements from a life cycle perspective

Environmental performances of different timber structures for pitched roofs