Weisheng Lu

An empirical investigation of construction and demolition waste generation rates in Shenzhen city, South China.

The construction and demolition waste generation rates (C&D WGRs) is an important factor in decision-making and management of material waste in any construction site. The present study investigated WGRs by conducting on-site waste sorting and weighing in four ongoing construction projects in Shenzhen city of South China. The results revealed that WGRs ranged from 3.275 to 8.791 kg/m(2) and miscellaneous waste, timber for formwork and falsework, and concrete were the three largest components amongst the generated waste. Based on the WGRs derived from the research, the paper also discussed the main causes of waste in the construction industry and attempted to connect waste generation with specific construction practices. It was recommended that measures mainly including performing waste sorting at source, employing skilful workers, uploading and storing materials properly, promoting waste management capacity, replacing current timber formwork with metal formwork and launching an incentive reward program to encourage waste reduction could be potential solutions to reducing current WGRs in Shenzhen. Although these results were derived from a relatively small sample and so cannot justifiably be generalized, they do however add to the body of knowledge that is currently available for understanding the status of the art of C&D waste management in China.

A framework for understanding waste management studies in construction

During the past decades, construction and demolition (C&D) waste issues have received increasing attention from both practitioners and researchers around the world. A plethora of research relating to C&D waste management (WM) has been published in scholarly journals. However, a comprehensive understanding of the C&D WM research is somehow absent in spite of its proliferation. The aim of this paper is to develop a framework that helps readers understand the C&D WM research as archived in selected journals. Papers under the topic of C&D WM are retrieved based on a set of rigorous procedures. The information of these papers is then analyzed with the assistance of the Qualitative Social Research (QSR) software package NVivo. A framework for understanding C&D WM research is created based on the analytic results. By following the framework, a bibliometric analysis of research in C&D WM is presented, followed by an in-depth literature analysis. It is found that C&D generation, reduction, and recycling are the three major topics in the discipline of C&D WM. Future research is recommended to (a) investigate C&D waste issues in wider scopes including design, maintenance and demolition, (b) develop a unified measurement for waste generation so that WM performance can be compared across various economies, and (c) enhance effectiveness of WM approaches (e.g. waste charging scheme) based on new WM concepts (e.g. Extended Producer Responsibility). In addition to the above research findings, the approach for producing the research framework can be useful references for other studies which attempt to understand the research of a given discipline.

Estimating and calibrating the amount of building-related construction and demolition waste in urban China

One side effect of the unprecedented urbanization in China is the large amount of building-related construction and demolition (C&D) waste generated during the process. It is an enigma why such statistics as C&D waste generation are absent from the literature in spite of their importance to devising sensible interventions to deal with the C&D waste-related problems. This paper aims to estimate the amount of C&D waste at the country level. It does so by adopting a methodology utilizing national statistical data and the average amounts of waste generated at work sites. Furthermore, the estimation undergoes a thorough calibration against various independent sources before it can be accepted confidently. It is finally estimated that approximately 1.13 billion tons of C&D materials were generated in China during 2014, which has declined from a plateau of building activities and C&D waste generation in the early 2010s. The paper provides some useful references for devising appropriate C&D waste reduction, reuse, or recycling strategies. The paper also offers useful commentary on methodology to estimate C&D waste generation at an urban level, particularly in situations where data availability is erratic.

The effects of green building on construction waste minimization: Triangulating ‘big data’ with ‘thick data’

In contrast with the prolific research examining the effects of green building (GB) on property value, energy saving, or indoor air quality, there has been minimal focus on GBs effects on Construction Waste Minimization (CWM), which is also an important aspect of cultivating sustainability in the built environment. To address this significant knowledge gap, this study has two progressive objectives: (1) to ascertain the empirical effects of GB on CWM and; (2) to identify and understand the causes leading to the ascertained effects. This is achieved by triangulating quantitative big data obtained from government agencies with qualitative thick data derived from case studies and interviews. The study found that BEAM Plus, the latest version of the Building Environmental Assessment Method developed by the Hong Kong Green Building Council (HKGBC), gave rise to a 36.19% waste reduction by weight for demolition works, but no statistically significant waste reduction for foundation or building works. It is because CWM, the basis for a demolition project to obtain GB credits, makes up only one of many ways for foundation or building works to earn credits, e.g., site aspects, lighting. In any case, CWM measures typically prove costlier means of acquiring credit, further causing developers to pay less attention to CWM in their GB tactics. The studys results, i.e., CWM in GB significantly influences demolition, but only marginally for foundation and building works, provide useful scientific evidence to inform GB councils and other responsible bodies and encourage continuous improvement in GB practices. While the study in general sheds light on how the triangulation of big, empirical data with conventional, qualitative data, e.g., interviews with GB professionals, helps to better understand the subject of the investigation, i.e., the effects of GB on CWM.