الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 164 |  |  |
| | | from | 164 | | |
Abstract
Self-compacting concrete SCC is a new category of high performance concrete with high workability and flow ability but without segregation. This concrete has the advantages of being cast easily under its own weight without the need of any external compacting energy. In addition, SCC is made of same ingredients of normal concrete NC in addition to extra fine material and special type of superplastictizer.
The current research studied the fire resistance of SCC compared with that NC. Both concretes were exposed to elevated degree of fire temperatures of 200 c, 400c,600c and 800c. In addition , the fire temperature was maintained at 800c while the concrete samples were exposed to such degree of temperature for time durations of 15, 30, 60 and 120 minutes. The samples were than cooled to room temperature using three different of cooling regimes namely, air cooling, CO2 powder cooling and water cooling.For studying the effect of aggregate type on the fire resistance of SCC and NC, three different types of local coarse aggregates were used namely, natural gravel, basalt and dolomite aggregates. Effect of incorporation of polypropylene fibers on the fire resistance of concrete was also investigated.This has been carried out through a detailed experimental program of 14 NC and SCC mixes. The mixes were made with free w/c of 0.45 and cement content of 400kg/m. Limestone powder of 80 kg/m was used in all SCC mixes. Three different dosages of sika viscocrete 5400 of 0.62. 0.75 and 0.87% by weight of cement were used in selected SCC mixes. Polypropylene fibers with 0.5% by weight of cement were used in selected NC and SCC mixes.
Fire resistance in terms of residual perentage in compressive strength and indirect tensile strength along with the extent of spalling as a result of exposure to fire were estimated. In addition, effect of fire on both porosity and absorption capacity of SCC and NC were also investigated. Improvements achieved with the incorporation of polypropylene fibers were also evaluated.This was carried out through detailed testing program in which concrete cubes were tested before and after exposure to fire for compressive strength, porosity and absorption spalling of concrete was evaluated using samples of concrete cubes that were exposed to elevated fire temperatures.
The results indicated that increasing the fire temperature caused a reduction in both compressive and tensile strength of concrete. The reduction obtained in SCC is less than that of NC for all used cooling regimes and aggregate types.Same has been confirmed by the results of spalling where spalling NC was found to be higher than that of SCC.Degradation of both NC and SCC increases with increasing te duration of exposure to a constant fire temperature of 800c.This become worse when water cooled regime has been used, since the results indicated than CO2 powder as a cooling regime provided the least extent of damage while water cooling regime provided the highest damage to the concrete samples. It is worth mentioning that the incorporation of polypropylene fibers inproved tensile strength, permeation properties and the concrete spalling of both NC and SCC. In addition, the results showed that, aggregate type has a minor effect on the concrete resistance to fire. Dolomite aggregates provided the highest resistance to fire while the natural gravel aggregate gave the least resistance.The diiference ranges from 5 to 10%.