Copyright © 2016 J. Constr. Build. Mater.  DOI: http: http://dx.doi.org/10.20936/JCBM/160105 *Address reprint requests to Sivakumar Naganathan, Department of Civil Engineering, College of Engineering, Universiti Tenaga Nasional, Block BN-3-024, Jalan IKRAM-UNITEN, Kajang 43000, Selangor, Malaysia. Email: sivaN@uniten.edu.my RESEARCH ARTICLE Use of Bottom Ash and Fly Ash in Masonry Mortar Sivakumar Naganathan 1* , Shojaeddin Jamali 2 , Sonny Silvadanan 1 , Tang Yew Chung 1 , and Mark Francis Nicolasselvam 1 1 Department of Civil Engineering, Universiti Tenaga Nasional, Malaysia 2 Civil Engineering and Built Environment School, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia INTRODUCTION The generation of solid wastes has increased during the last few decades. According to the Malaysian Environment Quality Report (2009), 1 the wastes which are being generated by the industries ac- cumulates up to 1,705,308 metric tons and are mainly consist of ash, dross, slag, clinker, gypsum, oil and hydrocarbon. By-products from the production of thermal power plants happen to be found abundantly in Malaysia. This country faces an increase in waste production, specifcally bottom ash and fy ash. Most of wastes end up in unmanaged landflls. As the result, landflling harm the environment through heavy metal pollution, erosion and leachate. Therefore, the use of bottom ash and fy ash will reduce the dis- posal of wastes and thus contributes to sustainable development. MATERIALS AND METHODS Cement used in this investigation met the requirements of MS 522 Part 1: (1989), specifcation for Portland cement. Bottom ash and fy ash were obtained from Kapar Energy Ventures Sdn. Bhd, Ka- par thermal power station, Selangor, Malaysia. The chemical and physical properties of constituent materials are given in Table 1. Fly ash had high percentages of silica and alumina, whereas cement composed mostly of calcium oxide which is known as quick lime. There were signs of loss of ignition in fy ash which mean that fy ash contains unburned carbon or other organic matters before the chemical analysis was performed. From the Blaine fneness test, cement was found to be fner than fy ash. The density of bottom ash was 836 kg/m 3 and was lower than that of cement and fy ash. Fly ash had the lowest specifc gravity compared to other ingredients. The low specifc gravity of fy ash is because of its low iron oxide (FeO 2 ) content. According to Das and Yudhbir, 2 for iron content greater than 10%, the specifc gravity is directly proportional to the iron content. This explains the high specifc gravity of bottom ash in comparison to fy ash as the bottom ash has higher iron oxide content. Fly ash class F was used for mixing. Bottom ash contains particles of various sizes from smaller than 2.36 mm to 20 mm. Bottom ash frstly was dried, and then sieved through 2.36 mm sieve to eliminate unsuitable materials and particles larger than 2.36 mm. Bottom ash and sand falls within the ranges given in ASTM C 144 (2003). 3 MIX PROPOSITION, CASTING AND CURING The mix proportions are indicated in Table 2. The materials were weighed according to the given ratio, and then were dry mixed for three minutes using spade. After which water was added until the mix was fowable. Next, the fowability test was conducted in accordance with ASTM D 6103 (2004). 4 The fow of all mixtures was fxed at 110 mm ± 5%. After that the water cement ratio for all mixtures was obtained. Three different sizes of molds were used for casting, viz. 50 mm × 50 mm × 50 mm, 70 mm × 70 mm × 70 mm and 60 mm × 40 mm × 220 mm. Sides of the molds were tapped by hammer to remove any trapped air bubbles. Then the molds were cured in the laboratory condition until the testing date. The cube and brick specimens were tested for compressive strength (ASTM C 109), 5 ultrasonic pulse velocity (ASTM C 597), 6 fexural strength (ASTM C 348), 7 chemical resistance (ASTM C 267), water absorptions (ASTM C 1403), risk of efforescence (ASTM C 67) 8 and fre resistance (ASTM C 109). The chemical resistance test was carried out along with the compressive strength to measure the resistance value. KEYWORDS bottom ash, compressive strength, durability, fly ash, mortar ABSTRACT Strength, durability and fre resistance of masonry mortar with incorporating fy and bottom ash with four different cement/ fne aggregate ratios of 1:3, 1:4, 1:5 and 1:6 were studied both in fresh and hardened states. Results showed that the mortar containing bottom and fy ash attained lower strength than that of the mixture without addition of ashes. Bottom ash and fy ash mortar specimens experienced excessive bleeding. However, based on ASTM C270, the coal ashes strength fell under the Type O mortar for mix ratio of 1:3 and 1:4. The presence of heat up to 200°C increases the compressive strength of mortar. Besides that, the use of fne aggregate restrains shrinkage of mortar bricks even with high water content. This study shows that use of coal ash wastes can be effectively utilised in mortar production. Received: 21 May 2016 – Accepted: 25 June 2016 – Published: 28 July 2016