Effects of hydroxyethyl cellulose and oxalic acid on the properties of cement

Publisher Summary Polymer-modified mortar and concrete are prepared by mixing either a polymer or monomer in a dispersed, powdery or liquid form with fresh cement mortar and concrete mixtures, and subsequently cured, and if necessary, the monomer contained in the mortar or concrete is polymerized in-situ. Several types of the polymer-modified mortars and concretes— namely, latex-redispersible polymer powder-, water-soluble polymer-, liquid resinand monomer-modified mortars and concretes are produced by using the polymers and monomer. Of these the latex-modified mortar and concrete are by far the most widely used cement modifiers. Although polymers and monomers in any form such as latexes, water soluble polymers, liquid resins, and monomers are used in mortar and concrete, it is very important that both cement hydration and polymer phase formation proceed well to yield a monolithic matrix phase, with a network structure in which the hydrated cement phase and polymer phase interpenetrate into each other. In the polymer-modified mortar and concrete structures, aggregates are bound by such a co-matrix phase. The superior properties of the polymer-modified mortar and concrete to conventional mortar and concrete are characterized by such a distinct structure.

Polymer-Modified Mortars and Concretes

The effect of polyacrylamide (PAA) addition in the ordinary cement and mortar, on the properties, such as setting time, heat of hydration, compressive and tensile strength has been studied by adding 0.5–5.0% additive by weight of cement. While hardness was determined using the Vickers indentation method, the fracture toughness of cementitious bond and flexural strength have been determined using three point bending system. Corrosion resistance of resulting products was tested against each of 0.1 and 1.0N of HCl and H 2 SO 4 and seawater. FT-IR and X-ray diffraction techniques have been employed to determine the phase compositions of the material. Polymeric phase is interspersed in cement causing decrease in water absorption and also its interaction with hydrating cement resulting additional bond formation leading to the increase in strength.

Juraj Gebauer

Papers

Preparation, properties & corrosion resistance of composites of cement mortar and organic polymers