The corrosion of reinforcement iron is one of the dangerous problems in middle and west of Iraq and Arabian gulf which is needed to large investigations because of increasing of chloride salts in soil and ground water and rising of temperature at summer which encourage of finding the shrinkage cracks in their two types : Plastic and drying shrinkage . cracks are easy way for harmful ions present at soil and ground water to enter through reinforced concrete making damage for protection film a rounding rein forced iron and led to rust with cracks in concrete cover a rounding rein forced iron added to its may be to cause structural damage in members of rein forced concrete because of absence of a adhesive between concrete and steel leading to structural failure . This research presents study for this problem and knowing their causes and methods to reduce it. Experimental work show that the concrete exposed to chlorides leads to decreasing in density with ratio (1.5%) and decreasing in flextural strength with ratio (138%) at age (28) day .
The presented work investigates the effect of addition admixture (cement kiln dust) to concrete as a partial replacement of cement weight. Cement kiln dust was added by (10,30,50)% of cement weight.Four mixes were selected, three of them contain cement kiln dust (CKD) and one reference mix without any admixture for ages (7,28,90) days. Compressive strength ,flexural strength, ultra-sound velocity (UPV), slump, splitting tensile strength and static modulus of elasticity were tested.The test results indicated that the use of (CKD) led to significant decreasing in concrete strength in general and this decreasing increases with the increasing of (CKD), for example at 28 day the compressive strength of reference concrete (A) was 35 MPa, while the compressive strength of (B,C,D) contain (10,30,50)%CKD were (28,25,22) MPa respectively.