Effect of ground bagasse ash on mechanical and durability properties of recycled aggregate concrete Rattapon Somna a , Chai Jaturapitakkul a,⇑ , Pokpong Rattanachu a , Wichian Chalee b a Department of Civil Engineering, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, Bangkok 10140, Thailand b Department of Civil Engineering, Faculty of Engineering, Burapha University, Cholburi 20131, Thailand article info Article history: Received 8 September 2011 Accepted 28 November 2011 Available online 8 December 2011 Keywords: A. Concrete C. Recycling E. Mechanical abstract In this study, bagasse ash, which is a large disposal landfill waste from sugar mill industries, is utilized as a pozzolanic material to improve the mechanical properties and durability of recycled aggregate con- crete. Ground bagasse ash (GBA) was used to replace Portland cement Type I at the percentages of 20, 35, and 50 by weight of binder. Compressive strength, modulus of elasticity, water permeability, and chloride penetration depth of the concretes were determined. The results revealed that the modulus of elasticity of recycled aggregate concrete with and without GBA was lower than that of conventional concrete by approximately 19%. GBA can be used effectively to reduce the water permeability of recycled aggregate concrete. The increase of GBA content in recycled aggregate concrete results in a significant decrease in chloride penetration depths. In addition, the mechanical properties and durability of recycled aggregate concrete were efficiently improved by using 20% of GBA in the concrete mixtures. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction In 2009, the total production of sugarcane in the world was esti- mated to be approximately 1661 million tons. The largest producer of sugarcane is Brazil and Thailand is the fourth largest [1]. The to- tal sugarcane production in Thailand was about 68.5 million tons [2]. Cordeiro et al. [3] suggested that the quantity of bagasse from the sugar production was approximately 26% of the sugarcane weight and the quantity of the bagasse ash from burning bagasse for producing electricity in the sugar industry was approximately 0.62% of the sugarcane weight which amounts to approximately 424,700 tons per year in Thailand. Many researchers have reported that bagasse ash with high fineness was a good pozzolanic material and its reactivity depends on the degree of crystallinity of silica, the presence of impurities, particle size, and fineness [4,5]. In Thailand, most of the bagasse ash has been disposed of to landfills and little of it is utilized then many landfills are required. Recycled coarse aggregate, the waste from construction activi- ties, has been used as a coarse aggregate in concrete. It has been found that the concrete made with it had lower compressive strength and lower modulus of elasticity than those of conventional concrete [6,7]. When the replacement was not more than 50% by weight, the modulus of elasticity of recycled aggregate concrete was slightly lower than that of conventional concrete [8]. Moreover, increasing of recycled aggregate as coarse aggregate in a concrete mixture resulted in higher of oxygen permeability and chloride ion penetration than those of conventional concrete [9,10]. However, recycled coarse aggregate could be used in structural concrete [11,12] and it has been shown to be suitable for structural use when it was used to replace natural coarse aggregate not more than 25% by weight [13]. In high strength concrete, the use of recycled coarse aggregate to replace natural coarse aggregate by not more than 30% by weight had no effect on the ultimate strength of concrete [14]. However, it is rarely found the study on the use of bagasse ash as a pozzolanic material in recycled aggregate concrete. Therefore, in this research, recycled coarse aggregate was used to fully replace natural coarse aggregate to produce recycled aggregate concrete and ground bagasse ash was used to partially replace cement to improve the mechanical properties and durability of recycled aggregate concrete. The novelty of this research is the utilization of the waste from sugarcane industries and waste from concrete works. Moreover, the results of this research are useful for concrete technology to select a suitable percent replacement of ground ba- gasse ash as well as recycled coarse aggregate to produce recycled aggregate concrete which has the good strength and durability. 2. Experimental program 2.1. Cement and bagasse ash This research used ordinary Portland cement Type I (OPC) and bagasse ash which was a by-product from sugar industry in 0261-3069/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.matdes.2011.11.065 ⇑ Corresponding author. Tel.: +66 2 470 9131; fax: +66 2 427 9063. E-mail address: chai.jat@kmutt.ac.th (C. Jaturapitakkul). Materials and Design 36 (2012) 597–603 Contents lists available at SciVerse ScienceDirect Materials and Design journal homepage: www.elsevier.com/locate/matdes