No abstract

Completing the construction projects as per the scheduled time is an underlined issue for the success of the projects. However, several construction projects are confronted in completing within the agreed contractual project duration. In addressing influential factors contributing to delay of delivery time in construction projects, a remarkable number of studies have been conducted and published over the past decades. However, it seems that a summary and organizing of the research development in this discipline is not popularized. Therefore, this paper aims to review the existing research trend on the factors causing delays in construction projects. The review is very useful for industry practitioners and scholars to provide comprehensive and precious sources. Also, it provides a discussion, conclusion, and future research directions.

Construction sites generate a large amount of material wastes and have become a common problem with associated risks in Ethiopia. However, the sources of such wastes are not well recognised. Therefore, the purpose of this research was to analyse the risk factors that contribute to material wastes in building construction projects. To achieve this goal, the factors that cause construction wastes were identified from literature and construction experts via focus group discussions and personal interviews. Following this, the factors were subjected to a questionnaire survey to identify the most critical factors of construction wastes. The questionnaire was distributed purposively to 85 construction experts representing contractors, consultants, and clients and 70 questionnaires were duly received for analysis. The data were analysed with a mean score and ranked to identify the most critical factors generating material wastes at construction sites. According to the results of the study frequent changes made to the design, poor strategies for waste minimisation, improper storage of material, poor site management, poor planning and supervision, and errors of contract document were the most critical factors causing construction wastes.

In Ethiopia, the rapid expansion of the construction sector has resulted in the wastage of construction materials that negatively affect the environment, society, and the economy. The reason is inefficient waste management strategies practiced in construction projects. Hence, an adequate material waste management strategy is required. This study was an attempt to identify the key techniques that can help to minimize material wastage in building construction projects. Questionnaire surveys, interviews, and reviews of previous studies and related literature were employed in gathering the relevant data. Seventy of 85 questionnaires administered and distributed to contractors, consultants, and clients were returned. These data were analyzed using the relative importance index method. The results indicated that employing waste management officers for this purpose, using prefabricated or off-site production of components, appropriate on-site waste management, and incorporating a policy of material waste minimization plan were identified as key measures to minimize construction material wastes.