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Factors influencing management of construction and demolition (C&D) waste within the Iranian context have yet to be investigated. The purpose of this paper is to define and address this knowledge gap, through development of a model to map the associations among the primary factors affecting C&D waste at project, industry and national levels.

A conceptual model is developed based on synthesising the findings of available studies on factors affecting C&D waste with a focus on developing countries. For collecting data, the study drew upon a questionnaire survey of 103 Iranian construction practitioners. The strength and significance of associations among these factors to modify and validate the model were assessed using the structural equation modelling-partial least squares approach.

Major factors affecting C&D waste management and their level of importance were identified at project, industry and national levels. Results clearly showed that the government should review regulations pertaining to C&D waste management and make sure they are implemented properly. The “polluter pays principle” is a useful guide in devising effective policies and regulations for the Iranian context.

This study contributes to the field through presenting the first major study on C&D waste management in Iran. The study provides a picture of C&D waste management status quo in Iran and encapsulates the factors affecting C&D waste management in the Iranian context at different levels within an integrated model. The findings have practical implications for policy makers and construction practitioners in Iran, similar developing economies and foreign firms planning to operate in Iran.

The short life cycle replacement of fitout in modern high-rise office buildings represents an under-researched waste problem. This paper aims to quantify the amount of demolition waste from office strip-out including attention to waste streams going to landfill, reuse and recycling.

Quantitative waste data (by weight) were measured from 23 office fitout projects situated in “A” grade office building stock from the Sydney CBD. Waste streams were measured separately for landfill, reuse and recycled materials. Descriptive and clustering statistics are presented and analysed.

From a total of 9,167 tonnes office fitouts demolished, 5,042 tonnes are going to landfill. The main contributor to landfill stream is the mixed waste generated in a fast-track demolition process. This approach partly resulted from the office interiors lacking regularity and easy disassembly. Moreover, considerable variability is observed in the waste per area, the waste streams and the waste compositions. Also, it is noteworthy that the recycled waste stream considerably increases when there exist economically viable conversion facilities, as for metals, hard fills and plasterboards.

The research is focused upon work practices that take place in Australia; therefore, generalisability is limited to situations that have similar characteristics. Future studies are needed to verify and extend the findings of this research.

A key area arising from the research findings is the need to design fitout with recycling and reuse in mind to divert more from landfill. This must explore and incorporate onsite demolition processes to ensure the design is well suited to commercially dominant processes in the overall demolition process, as well as attention to developing economies of scale and viability in re-sale markets for reused items.

Little empirical or quantitative research exists in the area of office fitout waste. This research provides entry to this area via quantifiable data that enables comparison, benchmarking and diagnostic ability that can be used to underpin strategic solutions and measurement of improvements.

The purpose of this paper is to investigate the effect of the replacement of natural coarse aggregate (NCA) with different percentages of recycled coarse aggregate (RCA) on properties of low calcium fly ash (FA)-based geopolymer concrete (GPC) cured at oven temperature. Further, this paper aims to study the effect of partial replacement of FA by ground granulated blast slag (GGBS) in GPC made with both NCA and RCA cured under ambient temperature curing.

M25 grade of ordinary Portland cement (OPC) concrete was designed according to IS: 10262-2019 with 100% NCA as control concrete. Since no standard guidelines are available in the literature for GPC, the same mix proportion was adopted for the GPC by replacing the OPC with 100% FA and W/C ratio by alkalinity/binder ratio. All FA-based GPC mixes were prepared with 12 M of sodium hydroxide (NaOH) and an alkalinity ratio, i.e. sodium hydroxide to sodium silicate (NaOH:Na₂SiO₃) of 1:1.5, subjected to 90^°C temperature for 48 h of curing. The NCA were replaced with 50% and 100% RCA in both OPC and GPC mixes. Further, FA was partially replaced with 15% GGBS in GPC made with the above percentages of NCA and RCA, and they were given ambient temperature curing with the same molarity of NaOH and alkalinity ratio.

The workability, compressive strength, split tensile strength, flexural strength, water absorption, density, volume of voids and rebound hammer value of all the mixes were studied. Further, the relationship between compressive strength and other mechanical properties of GPC mixes were established and compared with the well-established relationships available for conventional concrete. From the experimental results, it is found that the compressive strength of GPC under ambient curing condition at 28 days with 100% NCA, 50% RCA and 100% RCA were, respectively, 14.8%, 12.85% and 17.76% higher than those of OPC concrete. Further, it is found that 85% FA and 15% GGBS-based GPC with RCA under ambient curing shown superior performance than OPC concrete and FA-based GPC cured under oven curing.

The scope of the present paper is limited to replace the FA by 15% GGBS. Further, only 50% and 100% RCA are used in place of natural aggregate. However, in future study, the replacement of FA by different amounts of GGBS (20%, 25%, 30% and 35%) may be tried to decide the optimum utilisation of GGBS so that the applications of GPC can be widely used in cast in situ applications, i.e. under ambient curing condition. Further, in the present study, the natural aggregate is replaced with only 50% and 100% RCA in GPC. However, further investigations may be carried out by considering different percentages between 50 and 100 with the optimum compositions of FA and GGBS to enhance the use of RCA in GPC applications. The present study is further limited to only the mechanical properties and a few other properties of GPC. For wider use of GPC under ambient curing conditions, the structural performance of GPC needs to be understood. Therefore, the structural performance of GPC subjected to different loadings under ambient curing with RCA to be investigated in future study.

The replacement percentage of natural aggregate by RCA may be further enhanced to 50% in GPC under ambient curing condition without compromising on the mechanical properties of concrete. This may be a good alternative for OPC and natural aggregate to reduce pollution and leads sustainability in the construction.

The inclusion of pozzolans like pulverised fuel ash (PFA), silica fume (SF) and metakaolin (MK) enhances the properties of concrete both in fresh and hardened states. In the case of high performance concrete (HPC), their role in enhancing the workability, strength and durability is extremely significant. However HPC has been observed to be more vulnerable than normal strength concrete when exposed to elevated temperatures. This paper presents an overview and discusses the strength and durability performance of high‐performance pozzolanic concretes incorporating PFA, SF, and MK subjected to elevated temperatures. Various researchers have demonstrated that addition of silica fume causes HPC to perform poorly when subjected to elevated temperatures. Higher loss of strength and spalling risks are also associated with it. Addition of PFA and MK has been found to improve the fire performance of HPC both in terms of residual strength and durability.

Hong Kong is running out of both reclamation sites and landfill space for the disposal of construction and demolition waste. This paper reports on the findings of a study, consisting of a questionnaire survey, interviews and work‐site visits, to compare the use of low‐waste building technologies in public housing and private residential projects in Hong Kong. The results show that large panel formwork and prefabricated building components are widely used in public housing projects in Hong Kong. Due to the difference of the design with public housing, the use of smaller aluminium panel formwork is more common in the private housing projects. The barriers for the adoption of low‐waste building technologies in the private sector are identified and discussed.

Although the Trip‐ticket System (TTS) has been implemented to manage construction and demolition (C&D) waste in Hong Kong for over three years, problems still exist in the landfill disposal of the C&D waste. For example, it is reported that fees are difficult to collect from waste transporters for tipping the C&D waste at the landfill site. Based on an examination of the flexibility of the TTS, this paper proposes an e‐commerce model, namely the Webfill system, in order to enhance the TTS. The computational structure of the Webfill system is described and the usefulness of Webfill is evaluated based on a simulation which provides a direct comparison between the existing TTS and the Webfill‐enhanced TTS.

The unitized curtain wall system (UCWS), one of the prefabricated technologies, is increasingly attracting attention in the Hong Kong construction industry. However, this innovative technology still lacks on-site implementation in high-rise residential buildings. To promote its development, this study aims at identifying the influential factors of UCWS adoption in Hong Kong's high-rise residential buildings from a multi-stakeholder perspective.

Factors were first selected through an in-depth literature review and a semi-structured interview. Then the factors were validated through a questionnaire survey using Cronbach's Alpha Reliability Test. Next, the factors were ranked regarding their importance using mean-score ranking and standard deviation. Meanwhile, different stakeholders were clustered using an experimental factor analysis (EFA) model to find the shared preferences (namely common factors).

The result shows that reduction of construction time (B1) and insufficient site storage area (C1) are the most important factors. The six stakeholder groups were clustered into two segments. B1 and improved quality control are the shared interests. While C1 and the need of specification change are the common concerns.

There are two major breakthroughs in this study. First is the novelty of research objects. UCWS, particularly its application preference in high-rise residential buildings, has rarely been studied, yet it is urgently required. Second is the novel research perspective. The influential factors were studied from a multi-stakeholder perspective. Not only the significant factors for six specific stakeholders but also the shared preference for stakeholder groups was identified. The findings contribute to promoting UCWS more targeted, efficient and comprehensive, as well as demonstrating the collaborative possibilities of multi-stakeholders.

Present study focuses on scope of developing sustainable heat resistant concrete by adding steel fibre (Sf) and polypropylene fibre (PPf) along with partially replacement of ordinary portland cement (OPC) and natural fine aggregate with fly ash (FA) and granular blast furnace slag (GBFS). Replacement percentages of FA and GBFS were 40% and 50%, whereas Sf and PPf for fibre-added mixes were 1% by volume of concrete and 0.25% by weight of cement, respectively.

An experimental work had been carried out to make comparison between control mix (CM), fibre-added sustainable mix (SCMF) and fibre-added control mix (CMF) with reference to weight loss, mechanical strength (compressive, split and flexure) after exposed to room temperature (27°C) to 1000°C at the interval of 200°C for 4 h of heat curing followed by furnace cooling and then natural cooling. Furthermore, microstructural analysis was executed at 27°C, 400°C and 800°C, respectively.

Colour change and hair line cracks were started to appear at 600°C. Fibre-added control mix and sustainable mix did not exhibit any significant cracks as compared to control mix even at 1000°C. Major losses were occurred at temperature higher than 600°C, loss in compressive strength was about 70% in control mix, while 60% in fibre-added mixes. SCMF exhibited the highest retention of strength with respect to all cases of mechanical strength.

Present study is based on the slow heating condition followed by longer duration of heat curing at target temperature.

Present work can be helpful for the design engineer for assessing the fire deterioration of concrete structure existing near the fire establishment such as furnace and ovens. Building fire (high temperature for short duration) might be the further scope of work.

Concept of incorporating pozzolanic binder and calcareous fine aggregate was adopted to take the advantage pozzolanacity and fire resistivity. To the best of author’s knowledge, there is a scope for fill the research gap in this area.

The purpose of the study is to evaluate the suitability of post-fire curing for normal and Recycled Aggregate Concretes (RAC) with and without fibres.

The study includes the testing of RAC specimens, i.e. 150 mm cubes and cylinders with 300 mm length and 150 mm diameter with hybrid fibres (0.15% polypropylene fibres + 0.35% steel fibres) along with fly ash. The specimens were exposed to elevated temperatures between 400 to 700°C with 100°C intervals for 2 h of duration and the post-fire exposed samples were further subjected to water curing for a period of 7 days. The compressive strength, split tensile strength and Rebound Hammer Number (RHN) were measured at room temperature, after exposure to elevated temperatures and post-fire curing.

The result shows that the compressive strength reduces by a maximum of 61.25% for 700°C and maximum retain in strength, i.e. 71.2% (in comparison to specimens kept at room temperature) is observed for 600°C post-fire cured specimens. The split tensile strength reduces by more than half for 500°C and above temperatures, whereas 400°C specimens exhibits a significant regain in strength after post-fire curing. To validate the results of compressive strength, the Rebound Hammer test has been conducted. The RHN value decreases by 41.3% for 700°C specimens and the effectiveness of post-fire curing is observed to be considerable up to 500°C.

The conclusions from the study can be used in assessing the extent of damage and to check the suitability of post-fire curing in further continuing the utilisation of a fire damaged structure.

Utilisation of secondary materials like recycled aggregates and fly ash can be made in the production of concrete.

Specimens with fibres performed better when compared to specimens without fibres and post-fire curing is found to be effective up to 500°C.

The model and existing practice of the construction supply chain (CSC) in the United Kingdom (UK) and Australia was presented in this chapter. The policies and reports that support the practice of the CSC were examined in both countries. It was discovered from the review of literature that the UK has a more detailed report targeted at improving the CSC than Australia. However, both countries have a common factor affecting their CSC which originates from fragmentation experienced within their supply chain. Construction stakeholders in the UK and Australia believe that collaboration and integration are vital components for improving performance. The majority of the contractors in both countries embrace collaborative working for the sole purpose of risk sharing, access to innovation and response to market efficiency. However, most of the models developed for managing the CSC in the UK are built around building information modelling (BIM). Also, the reviewed studies show that supply chain management practice will be effective following the following principle: shared objectives, trust, reduction in a blame culture, joint working, enhanced communication and information-sharing. Finally, the UK has a more established framework and more CSC models compared to Australia.