الفهرس 
CHAPTER (1) : INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Fresh concrete may be susceptible to plastic shrinkage. Cracks that develop at early age can significantly impact the durability of concrete structures. While admixture has been advocated as a promising solution to mitigate the problem of plastic shrinkage cracking, little guidance exists to determine which type and what quantity of admixture should be used. Shrinkage is a volume reduction that is caused by moisture losses, temperature changes, and chemical reaction when this
shrinkage is prevented by the boundary restrains, stresses that develop may lead to shrinkage cracking. Shrinkage cracking can significantly reduce the durability of concrete structures. As plastic shrinkage cracking of concrete still causes considerable repair costs annually, an understanding of the phenomenon is essential to prevent its damage effects in the concrete structures. In this research, the chemical admixture as Super Absorbent Polymer (SAPs) and the mineral
admixture as Nano silica (N.S) were used as a new methodology to avoid the
shrinkage. This research studied the effect of the chemical and mineral admixtures on the behavior of concrete at early ages. The main parameters addressed in the research are the type of admixtures and ratio (N.S with 0.5, 1, 2 and 2.5% and SAPs with 0.2 and 0.3% as a percent of cement weight), method of curing (water, air of the laboratory (25 and 50% relative humidity) and open atmosphere (ranged from 10 to 45 and the relative humidity ranged from 40 % to 80 %)).
The compressive strength for the mixes were measured at ages (1, 3, 7 and 28
shrinkage was measured for 24 hours and dry shrinkage was measured for 620
days for the different mixes. Results from these testes show that the optimum ratio of N.S is 2.5% addition as percent of cement weight at water curing improve the behavior of concrete. Also The Using of 0.3% SAPs as a percent of cement
weight the best value to enhance the behavior with air curing as a self-curing of concrete specimens.