A Study on Polymer-Modified Mortar with High Flexural Strength
Zhixiang LIN
Abstract:This paper deals with the development of polymer-modified mortar with high flexural strength, which is used in place of ordinary cement concrete for the manufacture of precast products with thin thickness. A polymer-modified mortar using a polyacrylic ester emulsion and an ordinary cement concrete are prepared, and tested for the fresh properties and the mechanical properties, length change and durability after steam curing. The results showed excellent fresh properties and strength development, as well as improved mechanical properties and durability such as resistance to freeze-thaw, neutralization, chloride ion penetration, hydrochloric acid and sulfuric acid. The physical properties obtained were further considered from the stand point of the characteristics of the material used and thecomposition and structure of hardened mortar. After steam curing, the flexural, compressive and tensile strengths of this mortar were 15.3 Mpa, 78.0 Mpa and 6.7 Mpa at 14 days, respectively; thus, the flexural strength was 3.1 times higher and the tensile strength was 2.1 times higher compared with ordinary concrete under the same curing conditions. These flexural strength and flexural/compressive strength ratio of this mortar are higher than those of conventional ultra-high-strength concrete. Therefore, this mortar can be effectively used in thin wall concrete products which are to be produced without mechanical vibration (self-compacting). Key Words:Polymer-modified mortar, High-early-strength portland cement, Steam curing, High flexural strength, Durability, Concrete products