Great efforts have been exerted in reducing carbon emissions in design, construction and operation stages. However, little attention is paid to the quantification of carbon emissions in construction waste recycling at the end-of-life stage. This study aims to quantitatively analyze the carbon emission of construction waste in Shanghai City, PR China. A grey model is used to forecast the generation amount of construction waste, and a life cycle assessment is performed to estimate the carbon emission of construction waste. In this study, both the carbon emission of recycling activities (environmental costs), and the equivalent amount of carbon generated from alternative materials (environmental benefit) are considered. Here, recycling 1 ton (t) of construction waste in Shanghai can save 100.4 kg CO₂−e. The total carbon-emission-saving potential can be increased from 0.31 million t CO₂−e (2022) to 0.35 million t CO₂−e (2031). The carbon emission of recycling concrete, brick, steel, wood and mortar, identified as the key components of construction waste, is investigated. This research can help to reduce carbon emissions and further achieve carbon neutrality for Shanghai City. The proposed methods can also be applied to other regions, especially when the data for construction waste are insufficient.

The Hong Kong–Zhuhai–Macao bridge–related Hong Kong (HZMB-HK) project consists of a set of boundary crossing facilities and transport links that connect the main bridge (HZMB) to the Hong Kong territory. It is a featured large-scale public infrastructure project that involves construction works done above or near the sea. A number of accidents have occurred since the commencement of the project in November 2011. This study aims to analyze the construction accidents that occurred in the HZMB-HK project during the period from 2012 to the first half of 2017. The methodology comprises both quantitative and qualitative approaches. First, the safety performance of the project was quantitatively measured using three indicators: accident, fatality, and lethality rates. In this regard, it was identified that the safety performance of the project was worse than that of public work contracts and the construction industry in general. It was also found that fall and caught in-between were the deadliest types of accidents in the project. Second, eight fatal incidents that resulted in nine fatalities were qualitatively analyzed on the basis of relevant accident investigation reports. In this regard, it was found that of the nine decedents, five died from drowning. This indicates that working above or near the sea poses a high risk of drowning to construction workers. Furthermore, measures to prevent accidents in large-scale infrastructure projects such as the HZMB-HK project were analyzed in this study. This study adds to the construction safety body of knowledge by analyzing the accidents in a large-scale infrastructure project that involves both land- and sea-based construction works. The lessons from this study could help stakeholders, such as policy makers and practitioners, improve the safety performance of large-scale infrastructure projects worldwide.

Driving factors and obstacles in adopting structural steel in Hong Kong: Case studies