REV.CHIM.(Bucharest)♦68♦No. 10 ♦2017 http://www.revistadechimie.ro 2367 Mechanism of Cement Paste with Different Particle Sizes of Bottom Ash as Partial Replacement in Portland Cement NG HOOI JUN 1 , MIRABELA GEORGIANA MINCIUNA 1,2 *, MOHD MUSTAFA AL BAKRI ABDULLAH 1,3 *, TAN SOO JIN 3 , ANDREI VICTOR SANDU 1,2 , LIEW YUN MING 1 1 Center of Excellence Geopolymer and Green Technology (CEGeoGTech), School of Materials Engineering, Universiti Malaysia Perlis (UniMAP), Perlis, Malaysia. 2 Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Iasi, Romania 3 Faculty of Engineering Technology, Universiti Malaysia Perlis (UniMAP), Kangar, Perlis Manufacturing of Portland cement consists of high volume of natural aggregates which depleted rapidly in today construction field. New substitutable material such as bottom ash replace and target for comparable properties with hydraulic or pozzolanic properties as Portland cement. This study investigates the replacement of different sizes of bottom ash into Portland cement by reducing the content of Portland cement and examined the mechanism between bottom ash (BA) and Portland cement. A cement composite developed by 10% replacement with 1, 7, 14, and 28 days of curing and exhibited excellent mechanical strength on day 28 (34.23 MPa) with 63 μm BA. The porous structure of BA results in lower density as the fineness particles size contains high specific surface area and consume high quantity of water. The morphology, mineralogical, and ternary phase analysis showed that pozzolanic reaction of bottom ash does not alter but complements and integrates the cement hydration process which facilitate effectively the potential of bottom ash to act as construction material. Keywords: Bottom ash, Portland cement, pozzolanic properties, ternary phase analysis Manufacturing of Portland cement consists of high volume of natural aggregates which depleted rapidly in today construction field [1]. Hence, it is critical and necessary to discover a new substitutable material to replace and target for comparable properties as Portland cement with sustainable building material especially those materials that have hydraulic or pozzolanic properties. Coal combustion products increasing problem for landfilled with limited land and environment protection issues have raised concern throughout the world and this leads alternative way to recycle and produce value added product. Recycling the ash in cement is an environmentally friendly solution for cement industry [2]. Coal combustion products mainly composed of fly ash, bottom ash, boiler slags, and fuel gas desulfurization residues where have been used as construction material for over 2000 years that assessed by U.S. Environmental Protection Agency [3, 4]. Although there are many researchers and research towards reuse BA in varies area, actual utilization is still under 50wt% of total production [4]. The most commonly used of BA in construction field as fine and coarse aggregates, lightweight aggregates, road construction, embankments, building materials industry, raw material for ceramic industry and also other purpose in open cast mining or marine applications [5-7]. BA from coal combustion presents a high variability of its properties, thus understanding the chemical composition and pozzolanic reactivity of BA is needed. Chemically bottom ash is composed of silica, iron, calcium, and alumina with small amount of magnesium, and sulphate which the constituent is quite similar to Portland cement but still depending on the incineration of coal combustion [8]. In some cases, the high reactivity of bottom ash could cause some long term detrimental effects on the properties of final product [9], the physical properties of bottom ash is coarser particle with irregular and rough structures [10]. The chemical and physical properties make it suitable to replace in construction * email: mirabela.minciuna@yahoo.ro; mustafa_albakri@unimap.edu.my engineering application. However, the pozzolanic properties of bottom ash are highly dependent on physical characteristic of the original coal [11, 12]. For this reason, it is significant to understand the mechanism of hydration products of bottom ash in Portland cement as replacement. In this study, we fabricated new cement composite by mixing BA with OPC with direct replacement of BA into Portland cement. The aim of this study is to find out the chemical composition and ability of three different sizes (63, 75, and 150 μm) bottom ash hardened cement paste that prepared with 10 wt% replacement after 1, 7, 14 and 28 days of curing to describe the hydration process. By using the ternary techniques, there are furthered understanding on how the bottom ash replace into Portland cement effectively. Experimental part Materials and method An experimental procedure was performed to determine the effect of different sizes of bottom ash of curing at 1, 7, 14, and 28 days by 10% replacement of bottom ash into Portland cement. Mix was prepared by partial substitution of 10% BA with 90% of Portland cement. Portland cement used in this study is manufactured by Cement Industries of Malaysia Berhad (CIMA) and under an effective system of testing, control, and monitoring and complies with MS EN 197-1:2007. Whereas bottom ash is purchased from Manjung Coal-Fired Power Station, Lumut, Perak, Malaysia. Before utilization of different sizes bottom ash, additional grinding and sieving into 63, 75, and 150 μm is necessary in order to use as replacement and increase the specific area thereby reduce inter-particle friction while enhancing the chemical reactivity [5]. These BA had almost identical chemical components and only differs in particle size. Portland cement with 10 wt% of BA was prepared by mixing the original cement powder with different sizes of 63, 75, and 150 μm. The samples of size 50 x 50 x 50 mm 3 were fabricated. All samples will be demolded after 1 day