To cite this article: Senthil Muthalvan Renuka and Chockkalingam Umarani (2018). Effect of critical risk factors causing cost deviation in medium sized construction projects. Journal of Construction in Developing Countries, 23(2): 63-85.Abstract: Risk is the outcome of an event which may be predicted on the basis of statistical probability. Construction projects have inherent risks associated with it. The main aim of this paper is to identify the critical risk factors and to propose a model to find the probability of cost deviation in medium sized construction projects. A total of 46 risk factors were shortlisted based on pilot study and experts' opinion. A questionnaire survey was conducted among 223 various construction professionals each representing one project i.e. from 223 different projects. Based on factor analysis, 46 risk factors which influence the cost deviation in construction projects were classified under nine key risk groups viz. project scope and evaluation risk, work environment risk, documentation and legal framework risk, construction and operational risk, resource productivity risk, knowledge sharing risk, site supervision risk, financial viability risk and lean construction risk. Logistic regression analysis was also carried out to develop a model to find the probability of cost deviation in construction projects. It is concluded that the risk groups such as project scope and evaluation risk, site supervision risk, knowledge sharing risk and lean construction risk are having higher influence in the cost deviation in medium sized construction projects. By setting the effective baseline of the project like estimation of original project cost and detailed project report, cost deviations in medium size construction projects can be eliminated. Detailed recommendations are also provided.

Delays in a construction project can be regarded as a failure. This paper aims to investigate the causes of delay in Indian construction projects undertaken by private, government and nongovernmental organizations. In view of this 45 causes of delay were identified and developed the questionnaire for the quantitative confirmation of the most causes of delay. Consequently the questionnaire was distributed to construction professionals like Managers, Engineers and others. Subsequently the collected data was analyzed using statistical tool and the factors were measured and ranked under each group by importance index for various construction professionals. The results suggest that delays are mainly due to shortage of labours, shortage of construction materials and extra works (rework and change orders). The resources like manpower and materials are having highest contribution of about 24% compared to other sources. However this paper presents recommendations for a better project management techniques & procedures which can be adopted during conceptual & detailed planning phases of the project in order to minimize the construction delay.

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Autoclaved aerated concrete (AAC) is one of the most common types of lightweight cellular concrete, having a density of approximately one-fourth of that of conventional plain cement concrete. The use of industrial waste materials in concrete as a replacement for cement has garnered a lot of attention in recent years as a way to reduce the environmental effect of concrete. In this study, an attempt has been made to study the effect of AAC blocks made of industrial wastes such as fly Ash (FA) and ground granulated blast furnace slag (GGBS). Fly ash, along with different dosages of GGBS, was used as a partial replacement for cement in the production of AAC. For all the different dosages, microstructural analysis was performed using a Scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDAX), and Fourier transform infrared spectroscopy (FTIR). Mechanical performances of AAC were determined by conducting various tests like compressive strength, modulus of rupture, dry density, and water absorption. The results revealed that the dosage of “15% GGBS + 85% cement” has maximum compressive strength, modulus of elasticity, and modulus of rupture made of Class F Fly Ash when compared to Class C Fly Ash based AAC blocks. Besides, the incorporation of GGBS in the manufacturing process would increase the compressive strength of AAC up to 68%. Hence, it is recommended to use 15% GGBS + 85% cement as a potential rate of replacement, to improve the mechanical properties of AAC blocks significantly.

Lime masonry walls have been the initial type of masonry wall construction in the construction era. The minimally processed limestone extracted from the lime quarries gives a lesser carbon footprint than any other present-day construction material, making it a sustainable construction material in the construction industry and is the need of the hour. In this study, naturally fermented Bio-Additives, Jaggery and kadukkai were used to make lime mortar for the masonry prisms and walls, and the strength performance was investigated. The bio-additive and the lime powder combination were studied using a pH meter and pH strips to confirm their acidic/basic nature. The lime mortar was experimented with for its flexural strength using a beam specimen. The masonry prism study was initially made with stacked prisms and wall panels (English bond and Flemish bond) for testing compressive strength. The lime mortar thicknesses were varied into two for all the specimens of 10mm and 15mm for both the head and bed joints of the masonry. The experimental analysis revealed that a mortar thickness of 10mm masonry increased the wall's strength more than a mortar of 15mm thickness in the masonry, disproving the myth that higher mortar thickness in masonry increases the strength of the masonry. The mineralogical characterization of the mortar was carried out by SEM-EDAX to know the internal composition and morphological reactions, FTIR for the changes in the organic composition, and DSC-TGA to know the thermal properties of the mortar matrix. This study justifies the use of bio-additives-infused lime mortar for contemporary masonry projects.