No abstract

In this research characteristics of hardened concrete containing cement kiln dust and silica fume as a partial replacement of cement were studied. These characteristics inclusion on compressive strength, electrical conductivity, water sorptivity and accelerated corrosion, for each mixture X-ray diffraction were carried out for determined mineralogical analysis of the representative concrete sample. Concrete specimens were prepared with different ratios of CKD and constant ratio 15% SF as a partial replacement by weight of cement. The test results had revealed that The use of CKD as partial replacement of cement in combination with SF in concrete were shown best performance than use CKD only. The amount of 20% CKD in the presence 15% SF as a partial replacement by weight of cement were the optimum ratios can be used in concrete mixtures without lower on compressive. At 5%, 10% and 15% CKD with constant 15% SF at frequencies 0.12, 1.0 and 10 kHz, the electrical conductivity were increased with increased CKD amount, whereas beyond 15% CKD efficiency of electrical conductivity were decreased with increase CKD amount at all frequencies. But at (10% to 25%) CKD, sorptivity value were increased with increase CKD amount when comparison with control mixture. The replacing of cement with CKD and SF, giveabout-the same corrosion rate which clear shown from XRD analysis.

This research aimed to clarify the role of by-product materials, such as CKD with SF as partial replacement by weight of cement in concrete manufacturing and inclusion on different characteristics of concrete. Concrete test specimens were mixed with 0%, 5%, 10%, 15%, 20% and 25% (CKD) with 15% (SF) as partial replacement by weight of Cement (CEM I-52.5N). Fresh concrete properties have been evaluated by workability measurement slump test. While hardened concrete properties have been evaluated by compressive, split tensile and flexural strengths tests at ages 7, 28 and 56 days, but evaluated for bond strength, modulus of elasticity and chemical composition measurement with X-Ray Fluorescence at age of 28 days. The test results have revealed that the increase of CKD amount with fixed amount of SF in concrete mixtures as partial replacement by weight of cement leads to gradual decrease of fresh concrete workability. In concrete mixtures, 20% CKD in the presence of 15% SF as partial replacement by the weight of cement are the optimum ratios which can be used without any negative effect on mechanical properties compressive, indirect tensile, flexural and bond strength at all the ages of concrete. Also modulus of elasticity and bond strength increased by 8.81% and 0.69% respectively at the age 28 days compared with control mixture.