Effect of furfuryl alcohol on the properties of hydrated cement mortar
- PDF / 266,957 Bytes
- 10 Pages / 612 x 792 pts (letter) Page_size
- 22 Downloads / 225 Views
S.D. Khatri Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, India (Received 30 October 2002; accepted 6 February 2003)
The effect of furfuryl alcohol addition to ordinary cement on its properties, such as heat of hydration, setting time, compressive strength, and tensile strength was studied by adding 0.5–3.0% by weight of cement. Hardness was tested using the Vickers indentation method. Fracture toughness of cementitious bond and bending strength were determined using the three-point bending system. Corrosion resistance of resulting products was tested against 0.1 and 1.0 N HCI and H2SO4 and seawater, respectively. Water absorption/open porosity and microstructure were also determined. It was observed that strength, hardness, toughness, and corrosion resistance increase up to 3.0% addition of furfuryl alcohol in ordinary Portland cement. Polymeric phase was interspersed in cement, causing a decrease in water absorption/open porosity, and its interaction with hydrating cement caused additional bond formation, leading to the increase in strength. I. INTRODUCTION
Studies on the effect of organic monomer/polymer additions on the properties of cement products have attracted the interest of researchers1– 6 for developing new building materials. Organic additive interacts with the constituents of cement during hydration and produce new phases. With reactive monomer or polymer, substantial modification of the hydration and crystallization process occurs by the interaction of the additive with the new phases formed during the hydration of cement. The reactions in both organic-monomer- or polymer-modified cement pastes and plain cement mortar or concrete are of similar nature.7 Water reacts with Portland cement to produce C–S–H1 and calcium hydroxide in the beginning, which dissolves some calcium sulfate in it. The hydroxide ions interact with silica, and form a basic layer on the aggregates. Calcium ions under alkaline conditions react with the silica to form calcium silicate, which gets deposited on the aggregate surfaces. At this time, the organic monomer or polymer molecules associate in the layer on the aggregate surface through the Ca2+ or other cation linkage. The monomer/polymer molecules also bond to the surface of cement particles in the cement mortar and concrete. According to Ohma et al.7,8 monomer and polymer addition to the mortar and concrete reduced the porosity and changed the pore structure. Due to the pore refinement, organic additive significantly increases the resistance of cement mortar and concrete to chloride ion penetration and resistance to inorganic acids. J. Mater. Res., Vol. 18, No. 5, May 2003
http://journals.cambridge.org
Downloaded: 18 Mar 2015
The addition of water-soluble polymers permits the formation of highly workable paste with very little water. The additive acts as a lubricant, facilitating close packing of various constituents, which are then held tightly together causing higher strength and toughness observed in the modified cement produ
Data Loading...
