Constructing a new building or any other civil engineering project from scratch is a challenge for the construction industry as novelty designs may be produced by designers but they are often constructed by low skilled labor on site. The unique and sometimes complex nature of the construction sector arises because a large number of different professional groups have different interests and requirements, which often conflict with one another. In principle, each construction company aims to construct a project without any defects from the very first activity on site right up to final completion. This aim is almost impossible to achieve throughout the entire construction duration because of many factors, including: low skilled labor, difficult site conditions, and incomplete designs, varying quality cultures in each company, poor communication and poor management. Therefore, construction defects are things which we can assume to have occurred on the site. Defects occurring during the construction process are sometimes costly and preventable mistakes. Research has shown that correcting defective components that are identified late in the construction process or during the maintenance period accounts for approximately 15% of the total construction costs. This paper presents a case study of the defects that occurred during a motorway construction project as a consequence of poor workmanship by an untrained workforce and it aims to raise awareness of the need for on-the-job training for quality managers in order to minimize defective works and reduce the project costs spent on correcting them. It also identifies the various factors that cause construction defects and suggests measures that can be taken to reduce them.
Authors:Esat Gashi, Ljupčo Dimitrievski, and Darko Ilievski
Asphalt paved roads prematurely exhibit a cracking pattern similar to that in the old underlying pavement. The cracking in the new overlay surface is due to the inability of the overlay to withstand shear and tensile stresses created by movements concentrated around preexisting cracks in the underlying pavement. This movement may be due to traffic loading causing differential deflections at cracks in the underlying pavement layers, expansion or contraction of subgrade soils, expansion or contraction of the pavement itself due to changes in temperature, or combinations of these phenomena. Due to heavy deformation of asphalt paved surface, using European funds, the Government of Macedonia initiated rehabilitation of Corridor X close to the Tetovo section. For the reconstruction of this important section of the motorway, an experimental programme was conducted to determine the effects of geogrid reinforcement on mitigating reflection cracking in asphalt overlays. The objective of this study is to assess the inclusion of geogrid in the pavement cross-section and the accumulation of permanent deformation. The geogrid position, type of existing pavement, temperature, and joint/crack opening were analyzed in three site trial tests. Crack propagation under repeated loading was monitored as well. The results indicate a significant reduction in the rate of crack propagation in reinforced samples compared to unreinforced samples of old asphalt pavement. The presented pavement design procedure could be tailored to the specific needs of the project and implemented in various road rehabilitation projects.