Monday, 18 June 2018

Properties and Thermal Stress Analysis of Blended Cement Self-Compacting Concrete

Properties and Thermal Stress Analysis of Blended Cement Self-Compacting Concrete

Self-Compacting concrete is a concrete that is able to flow and consolidate under its own weight, completely fill the formwork even in the presence of dense reinforcement, whilst maintaining homogeneity and without the need for any additional compaction. Self-Compacting concrete is achieved by using high proportions of powder content and super? plasticizers. Due to this, pronounced thermal cracking is anticipated. Thermal cracking in concrete structures is of great concern. The objective of this research is to carry out experiments and investigate fresh and hardened properties of SCC developed using a blend of ordinary Portland cement and ground granulated blast furnace slag (GGBFS), to evaluate the applicability of Japan Concrete Institute (JCI) model? equations and? to find out any similarities and differences between Self-? Compacting concrete and normal vibrated concrete—Portland blast furnace slag concrete class B. Thermal stress analysis of the proposed Self-Compacting concrete and normal vibrated concretes were investigated by simulation using 3D FEM analysis. To carry out these objectives, concrete properties such as autogenous shrinkage, adiabatic temperature rise, drying shrinkage, modulus of elasticity, splitting tensile strength and compressive strength were determined through experiments. From experimental results, it was observed that except for the fresh properties, the hardened properties of Self-Compacting exhibit similar characteristics to those of normal vibrated concrete at almost similar water to binder ratios. It was also established that Self-Compacting concrete at W/B of 32% with a 50% replacement of ground granulated blast furnace slag has better thermal cracking resistance than SCC with 30% GGBFS replacement. It is also found that provided the relevant constants are derived from experimental data, JCI model equations can be applied successfully to evaluate hardened properties of Self-Compacting concrete.

Major Determinants of Prices Increase of Building Materials on Ghanaian Construction Market

Major Determinants of Prices Increase of Building Materials on Ghanaian Construction Market

Prices increase of building materials is a common trend in both developed and developing countries. The prices increase of building materials results in high cost of housing. The aim of this study is to identify the major determinants of prices increase of building materials on Ghanaian construction market, and also to assess the relationship between the independent variables of the prices increase. A five-point Likert scale was used for the study; from strongly disagree (1) to strongly agree (5). The variables in the questionnaire were ranked based on the response of the participants of the study using Mean Response Analysis (MRA) statistics. Spearman correlation matrix was used to determine the relationship between the variables of prices increase of building materials. Crude oil prices, energy cost, local taxes and charges, cost of fuel and power supply, high running cost, high prices of raw materials, cost of transportation and the high cost of labor were found to be the major determinants of prices increase of building materials on Ghanaian construction market. The study further found multicollinearity relationship among variables of prices increase of building materials, of which the highest correlation coefficient was found between fast-growing demand due to high global economic growth and over-dependence on imported building materials. The study recommends that further research should be carried out to determine the control measures of increasing prices of building materials in Ghana.

Properties and Thermal Stress Analysis of Blended Cement Self-Compacting Concrete

Properties and Thermal Stress Analysis of Blended Cement Self-Compacting Concrete Self-Compacting concrete is a concrete that is able to...