BEHAVIOR AND BONDING CHARACTERISTICS OF SELF-COMPACTING CONCRETE | ||
| JES. Journal of Engineering Sciences | ||
| Article 4, Volume 35, No 1, January and February 2007, Pages 53-69 PDF (1.66 M) | ||
| Document Type: Research Paper | ||
| DOI: 10.21608/jesaun.2007.111401 | ||
| Authors | ||
| Ashraf M. Heniegal* ; Walid S. Elsayed | ||
| Civil structures dept., faculty of industrial education, Suez Canal univ., Suez, Egypt | ||
| Abstract | ||
| Self-compacting concrete, also referred to as self-consolidating concrete, is able to flow and consolidate under its own weight and is deaerated almost completely while flowing in the formwork. It is cohesive enough to fill the spaces of almost any size and shape without segregation or bleeding. This makes SCC particularly useful wherever placing is difficult, such as in heavily-reinforced concrete members or in complicated formworks. Considering the economy and the durability of our present concrete structures, the quality and the density of the concrete cover, as well as the compaction of the concrete are main parameters [1]. The objectives of this research were to compare the Splitting Tensile Strength and Compressive Strength values of self-compacting and normal concrete specimens and to examine the bonding between the coarse aggregate and the cement paste using the Scanning Electron Microscope. Cylinder specimens (8″ by 4″) were tested for Splitting Tensile and Compressive Strength after 28 days of standard curing, in order to find out if self-compacting concrete would show an increase in these strengths and a better bonding between aggregate and cement paste, compared to normal concrete. The mix design used for making the concrete specimens was based on previous research works from literature. The water – cement ratios varied from 0.3 to 0.6 while the rest of the components were kept the same, except the chemical admixtures, which were adjusted for obtaining the self-compactability of the concrete. All SCC mixtures exhibited greater values in both splitting tensile and compressive strength after being tested, compared to normal concrete. The splitting tensile strength increased by approximately 30%, whilst the compressive strength was around 60% greater. In addition, the SCC tensile strengths after 7 days were almost as high as those obtained after 28 days for normal concrete. This was possible due to the use of mineral and chemical admixtures, which usually improve the bonding between aggregate and cement paste, thus increasing the strength of concrete. Images taken from concrete samples having water-cement ratios of 0.3, 0.4, and 0.6, using the Scanning Electron Microscope, have shown that the widths of the physical interface micro cracks were greater for normal concrete than for self-compacting concrete, which implies that the aggregate-cement bonds were better for SCC than for normal concrete. | ||
| Keywords | ||
| self-compacting concrete; splitting tensile; compressive strength; physical interface | ||
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