Construction labor productivity (CLP) is a critical measure of efficiency in the construction industry. This bibliometric review comprehensively analyzes global research trends in CLP monitoring over the past 56 years. The review identifies the top journals, authors, and nations contributing to this field and highlights a significant increase in publications since 2000. The co-authorship bibliometric map illustrates how different nations collaborate in research, with Europe and Asia being the most engaged regions in the study of CLP monitoring. The author keyword co-occurrence analysis indicated the need for more consistent and reliable measurements of CLP in the field. Furthermore, the review highlights the importance of factors such as occupational health and safety, change orders, and the adoption of lean construction principles and innovative technologies for monitoring and improving CLP. Finally, we evaluated the characteristics of different modeling approaches utilized in CLP monitoring studies, considering factors such as data availability, the complexity of relationships, and the required expertise. This study highlights the need for real-time and transparent CLP monitoring methods. Overall, this study contributes to the research field by offering insightful information on the current state of CLP monitoring and proposing potential future directions for research.

Purpose: Activity sampling is a technique to monitor onsite labourers' time utilisation, which can provide helpful information for the management level to implement suitable labour productivity improvement strategies continuously. However, there needs to be a review paper that compiles research on activity sampling studies to give readers a thorough grasp of the research trend. Hence, this paper aims to investigate the activity sampling techniques applied in earlier research from the angles of activity categories formation, data collection methods and data analysis.Design/methodology/approach: The method used in this paper is a systematic review guided by the PRISMA framework. The search was conducted in Scopus and Web of Science. The inclusion and exclusion criteria were applied, selecting 70 articles published between 2011 and 2022 for data extraction and analysis. The analysis method involved a qualitative synthesis of the findings from the selected articles.Findings: Activity sampling is broadly divided into four stages: targeting trade, determining activity categories, data collection and data analysis. This paper divides the activity categories into three levels and classifies the data collection methods into manual observation, sensor-based activity sampling and computer vision-based activity sampling. The previous studies applied activity sampling for two construction management purposes: labour productivity monitoring and ergonomic safety monitoring. This paper also further discusses the scientific research gaps and future research directions.Originality/value: This review paper contributes to the body of knowledge in construction management by thoroughly understanding current state-of-the-art activity sampling techniques and research gaps.

Soluble silica from palm oil clinker was extracted using Laine’s method. It involved two major steps, namely water reflux and distillation. The use of 480 g of POCP and 12 hours of distillation in the extraction experiment resulted in 53.50% of dissolved silica, which was the highest gain among the trial experiments and was chosen as an optimum parameter for the subsequent characterisation analysis. In addition, its effect on cement hydration was studied by including it as a filler in mortar mixtures. Mortar with 7.50% of extracted silica gained high strength in the early days of curing and performed well throughout the maturing age. The rapid hardening properties of soluble silica-based mortar would promote the potential of soluble silica as an additive for rapid hardening.

The application of Bluetooth Low Energy (BLE) systems for labour tracking on construction sites is a popular research trend. Strategic system deployment is crucial for ensuring the overall reliability and feasibility of these systems. This study aims to identify the optimal BLE system deployment strategy for tiling work zones in three different renovation sites. The BLE system consists of BLE beacon, BLE gateway, Raspberry Pi (data logger), and MATLAB for data analysis. To ensure optimal placement of the BLE gateway, site visits were conducted to evaluate various conditions, such as power supply availability, signal blockage by structures, and potential disruption to the tiling work. In addition, the beacon transmission (Tx) levels were adjusted to enhance the detection accuracy of the system. The findings show that the optimum beacon Tx powers at sites A, B, and C are -12dBm (86.3% accuracy), -16dBm (94.6% accuracy), and -16dBm (91.1% accuracy), respectively. These findings will be adopted in future research on these sites. The study contributes to the understanding of optimal BLE system deployment strategies in construction sites, which can improve labour tracking accuracy and overall project management.