A Study of Mix Design of Concrete Hollow Blocks Using Crushed Powder Like Glass as Supplementary Aggregates
Chapter I
Introduction
Concrete has been used in the construction industry for centuries. A typical concrete is a mixture of fine aggregate (sand), coarse aggregate (rock), cement, and water. Nowadays the usage of concrete is increasing from time to time due to the rapid development of construction industry.Today, there are many ways to enhance the quality and properties of concrete. One of the technological advances in improving the quality of concrete is Self-Consolidating Concrete.
Self-Consolidating Concrete (SCC) has been described as "the most revolutionary development in concrete construction for several decades". Originally developed to reduce the need of skilled laborers for concrete filling in construction. It has proved beneficial economically because of a number of factors. For example, fasterconstruction, reduction in site manpower, better surface finishes, easier placing, improved durability, greater freedom in structural designthinner concrete sections, safer working environment, and reduced noise levels by the absence of concrete vibrators.
According to Welton (1987), Vibration of fresh concrete has five objectives and as follows:
1. Elimination of mechanical voids in the mass.
2. Elimination of unintentional air voids.
3. Removal of unnecessary water.
4. Shaking the particles in the mix into their closest nesting, providing uniform dispersion and distribution of the large particles, but still retaining the coating of all particle surfaces with cement mortar.
5. Reduction of micro-pores and micro-capillaries.
According Forssblad (1987) unvibrated fresh flowing concrete has thefollowing shortcomings and as follows: 1. It contains a number of small and medium size air bubbles. 2. There is reduced bond strength to reinforcement. 3. There are often settlement cracks around steel rebars.
Originally developed in Japan, SCC technology was made possible by the much earlier development of Superplasticizers for concrete. SCC has now been taken
Introduction
Concrete has been used in the construction industry for centuries. A typical concrete is a mixture of fine aggregate (sand), coarse aggregate (rock), cement, and water. Nowadays the usage of concrete is increasing from time to time due to the rapid development of construction industry.Today, there are many ways to enhance the quality and properties of concrete. One of the technological advances in improving the quality of concrete is Self-Consolidating Concrete.
Self-Consolidating Concrete (SCC) has been described as "the most revolutionary development in concrete construction for several decades". Originally developed to reduce the need of skilled laborers for concrete filling in construction. It has proved beneficial economically because of a number of factors. For example, fasterconstruction, reduction in site manpower, better surface finishes, easier placing, improved durability, greater freedom in structural designthinner concrete sections, safer working environment, and reduced noise levels by the absence of concrete vibrators.
According to Welton (1987), Vibration of fresh concrete has five objectives and as follows:
1. Elimination of mechanical voids in the mass.
2. Elimination of unintentional air voids.
3. Removal of unnecessary water.
4. Shaking the particles in the mix into their closest nesting, providing uniform dispersion and distribution of the large particles, but still retaining the coating of all particle surfaces with cement mortar.
5. Reduction of micro-pores and micro-capillaries.
According Forssblad (1987) unvibrated fresh flowing concrete has thefollowing shortcomings and as follows: 1. It contains a number of small and medium size air bubbles. 2. There is reduced bond strength to reinforcement. 3. There are often settlement cracks around steel rebars.
Originally developed in Japan, SCC technology was made possible by the much earlier development of Superplasticizers for concrete. SCC has now been taken
Bibliography: Manual for Testing Self-Compacting Concrete (Cemex Inc.) MohdFakri Bin Muda (2010) CristianDruta (2009). Tensile Strength and Bonding Characteristics of Self Compacting Concrete, Polytechnic University of Bucharest .