الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Concrete deterioration caused by Sulfates and Chlorides has occurred extensively in deep foundations. The extent of deterioration depends on the properties of the concrete (cement content. water/cement ratio. cement type. aggregate type. and concrete cover thickness) and on the aggressive environment properties. In addition to the concentration of the Sulfate, the speed with which concrete is attacked depends also on the rate at which the Sulfate -removed by the reaction with cement- can be replenished. Thus. in estimating the danger of Sulfate attack, the movement of groundwater has to be consiClered. Soil permeability is the factor that govems the ease in which the contaminated water can move around and be replaced. Concrete attacked by Sulfate has a characteristic whitish appearance. Progressive cracking and spalling usually follow the damage that starts at edges and comers, which reduces the concrete to a friable or even soft state. Chlorides attack concrete by causing corrosion of the contained reinforcement resulting in formation of Ferrous Hydroxide followed by the formation of Hydrated Ferric Oxide (Fe20J)’ The formation of Fe20J results in enlargement in the volume of reinforcement causing excessive intemal forces leads to cracking in concrete. An experimental study were carried out to investigate the effect of soil (sand and silty loam) contaminated with 5% Magnesium Sulfate (MgS04), 5% Sodium Sulfate (Na2S04), and 10% Sodium Chloride (NaCI) solutions on the durability of 64 models of concrete pile embedded in such environment. Different four types of cement (Ordinary Portland Cement, Sulfate Resisting Portland Cement, High Slag Cement, and Blastfumace Slag Cement) were used in the pile models with limestone and gravel aggregate with two concrete-cover thickness in case of chlorides environment. The durability tests were extended up to one year.
The pile models were water-cured for 28 days before being tested to get the initial weight and Ultrasonic Pulse Velocity and then two metal measuring points were mounted on the pile skin ISO ± 0.02 mm apart in axial direction before embedment in the contaminated soil.
After one year of exposure, the piles were extracted, cleaned, visually inspected and tested to get the final weight, Half-Cell Potential Difference, Ultrasonic Pulse Velocity and Length Change. After carrying out the previous nondestructive tests, the
piles were cut to have two 20cm cylindrical segments. One segment had a
compression test and the other had a splitting tension test that’s before retrieving the 6< - ~ ~ 8 D
reinforcement for visual inspection.