Abstract—Due to their fluidity and simplicity of use, self- compacting concretes (SCCs) have undeniable advantages. In recent years, the role of metakaolin as a one of pozzolanic materials in concrete has been considered by researchers. It can modify various properties of concrete, due to high pozzolanic reactions and also makes a denser microstructure. The objective of this paper is to examine the influence of three type of Portland cement and metakaolin on fresh state, compressive strength and sulfuric acid attacks in self- consolidating concrete at early age up to 90 days of curing in lime water. Six concrete mixtures were prepared with three types of different cement as Portland cement type II, Portland Slag Cement (PSC), Pozzolanic Portland Cement (PPC) and 15% substitution of metakaolin by every cement. The results show that the metakaolin admixture increases the viscosity and the demand amount of superplasticizer. According to the compressive strength results, the highest value of compressive strength was achieved for PSC and without any metakaolin at age of 90 days. Conversely, the lowest level of compressive strength at all ages of conservation was obtained for PPC and containing 15% metakaolin. According to this study, the total substitution of PSC and PPC by Portland cement type II is beneficial to the increasing in the chemical resistance of the SCC with respect to the sulfuric acid attack. On the other hand, this increase is more noticeable by the use of 15% of metakaolin. Therefore, it can be concluded that metakaolin has a positive effect on the chemical resistance of SCC containing of Portland cement type II, PSC, and PPC. Keywords—SCC, metakaolin, cement type, durability, compressive strength, sulfuric acid attacks. I. INTRODUCTION ODAY, verification of the durability of concrete is an important issue for the prevention of concrete degradation with respect to aggressive agents in the environment. The mix design of SCC is different from that of a normal concrete and therefore its durability characteristics are still uncertain. In this way, the study of the effective durability effects of SCC against aggressive agents is an important point on the life of Kianoosh Samimi is with the Research and Development Service, Imen Rah Consulting Engineering Co., No7, 4th.St Khaled Eslamboli (vozara) Ave. Tehran, Iran (phone: 0098-21-88707051; fax: 0098-21-88707052; e-mail: samimi.kianoosh@imenrah.com). Farhad Estakhr is with the Department of Civil and Engineering, Islamic Azad University, Marvdasht, Iran (e-mail: farestakhr@yahoo.com). Mahdi Mahdikhani is with the Department of Engineering and Technology, Imam Khomeini international University, Noruzian Blvd., Qazvin, Iran (e-mail: mahdikhani@aut.ac.ir). Faramaz Moodi (Research Assistant) is with the Department of Civil and Environmental Engineering, Amirkabir University of Technology, Hafez Ave, Tehran, Iran (e-mail: fmoodi@aut.ac.ir). concrete structures. The presence of acids such as sulfuric (H 2 SO 4 ) and hydrochloric acids (HCl) usually originates in factories located in industrial areas, otherwise they are sometimes due to urban activities. Concrete infrastructure members can be degraded by the attack of sulfuric acid present in groundwater, such as chemical wastes generated by the oxidation of sulfur compounds (e.g., pyrite) in the embankment [1]. Concrete is a strongly basic medium with a pH of 13. In contact with an acidic medium with a pH of less than 7, the chemical equilibrium of the hydrates is destabilized. In the case of the different hydrates, the stability of the various hydrates is variable [2]. Thereby, portlandite is an element by high solubility which it is very sensitive to an aggressive attack indicating that the dissolution of the portlandite initiates for a pH below 12.5. In acid attack, the flux of transported ions will cause, on the one hand the dissolution of the hydrates previously formed and, on the other, the precipitation of the new compounds leading to the progressive degradation of the concrete [3]. The aggressiveness of the attack depends on the different elements such as the solubility of the salts formed due to the production of the acid-base reaction as calcium, aluminum, iron and magnesium salts, the aggressive acid species and the pH of the solution attack [4]. Mineral additions play an important role in the physical, mechanical, and chemical properties of cementitious composite. The use of cementitious additives modifies the nature and texture of hydrates [5]. The use of cementitious additives is for purpose to reduce the consumption of cement by contributing in a simple and economical way to solve the problems related to the environment. The cementitious additions interact with the cement paste in two forms: • Hydraulic reaction: in this case, using the filler effect, the particle sizes improve the compaction of the mixture and thereby minimize the transport of fluid in the cementitious matrix. • The pozzolanic reaction: A siliceous or alumino-siliceous compound reacts in the presence of water with the portlandite created during the hydration of the cement in order to form binder compounds (C-S-H). The pozzolan influences the structure of the pores, not only because of the pozzolanic reaction, but also because they can infiltrate between the grains of cement and serve as nucleation points for the formation of hydrates. This generates a densification of the structure which leads to an improvement on the properties of the hardened cement paste at the level of Kianoosh Samimi, Farhad Estakhr, Mahdi Mahdikhani, Faramaz Moodi Resistance to Sulfuric Acid Attacks of Self-Consolidating Concrete: Effect Metakaolin and Various Cements Types T World Academy of Science, Engineering and Technology International Journal of Civil and Environmental Engineering Vol:12, No:3, 2018 237 International Scholarly and Scientific Research & Innovation 12(3) 2018 scholar.waset.org/1307-6892/10008646 International Science Index, Civil and Environmental Engineering Vol:12, No:3, 2018 waset.org/Publication/10008646