American Journal of Engineering Research (AJER) 2013 www.ajer.org Page 103 American Journal of Engineering Research (AJER) e-ISSN : 2320-0847 p-ISSN : 2320-0936 Volume-02, Issue-09, pp-103-109 www.ajer.org Research Paper Open Access Effect of NGBFS and CBA as fine aggregate on the chloride permeability of concrete İsa Yüksel 1 , Ozan Demirtaş 2 1 Department of Civil Engineering ,Bursa Technical University, Bursa, Turkey 2 4D Architecture & engineering Services Ltd., Zonguldak, Turkey Abstract: - This paper presents the results of an investigation which was about influence of non-ground Coal Bottom Ash (CBA) and Non-Ground Granulated Blast-Furnace Slag (NGBFS) as fine aggregate on rapid chloride permeability of concrete. Series of Rapid Chloride Permeability Test (RCPT) were conducted with concrete specimens containing NGBFS and CBA in varying percentages from 10 to 50% with the step of 10% of fine aggregate by weight. Two basic series concrete specimens were prepared in laboratory. The first series (G) was contained NGBFS, the second series (B) was contained CBA as fine aggregate. Test results indicated that NGBFS or CBA improves the resistance to chloride ion penetration to some extent. 30% and 10% replacement ratios were selected as optimum replacement ratios for G and B series. It was concluded that GBFS was more impressive then CBA for blocking chloride ion movements. Keywords:- Aggregate, Chloride permeability, Coal bottom ash, Concrete, Granulated blast-furnace slag. I. INTRODUCTION Chloride attack is accepted one of the principal cause for concrete degradation. Chloride ions were generally known as the most harmful agent for reinforced concrete. Mostly, low level of chloride ions can be tolerated in durable concrete. However, excessive chloride levels cannot be tolerated and it may occur over the service life by reason of external chloride sources. Mineral admixtures such as ground blast furnace slag or ground fly ash were currently used to improve durability of cement and concrete. At the same time, researches are in progress on the use of non-ground industrial by-products or industrial wastes such as non-ground granulated blast furnace slag (NGBFS) and coal bottom ash (CBA) in concrete as fine aggregate. Rapid Chloride Permeability Test (RCPT) approach was a relatively simple and quick test for measuring the permeability of concrete indirectly. This test shows quickly the general behavior of concrete permeability that is an important parameter for concrete durability. Production of durable concrete is a critical issue in order to gain economic, ecologic and technical advantages for the future of the concrete industry. The objective of presented study was to make a comparative investigation of the influence of NGBFS and CBA on rapid chloride permeability of concrete. A series of RCPT is conducted on concrete specimens incorporated NGBFS and CBA in varying percentages by weight as fine aggregate. II. PREVIOUS WORK Usually it is not possible to prevent chloride entrance in concrete. Chloride penetration into concrete is a critical issue in the process of corrosion of reinforcing steel bars. The problem is particularly acute in a marine environment, in bridges and roadways subjected to deicing salts, and in parking garages into which salt is transported from salted roadways [1]. The chloride ingress depend on the sorptivity and chloride diffusivity of concrete, ability of concrete to bind chlorides, water/cement ratio, chloride diffusivity of aggregates, alkalinity of the binder, degree of exposure to chloride source, temperature, carbonation, hydrostatic head. Chloride ions can destroy the passive oxide film on reinforcement steel in concrete, even at high alkalinities [2]. The amount of chloride required to initiate rebar corrosion depends on the pH of the solution in contact with the reinforcement steel.