Mechanical Properties of Fluoropolymer Modified Mortar

Abstract

In past lot of experimental studies were carried out on polymer modified cement (PMC) mortar and concrete modified using polymers such as SBR, acrylic, VAE and integral waterproofing agents. The advantages of PMC mortars such as good bond strength, decrease in water cement ratio, higher strength, lower permeability etc. makes it suitable for use as repairing and water proofing material. Fluoropolymers are fluorocarbon based product which is used as water repellent in fabric industry. These are widely used for water and oil repellence and offer good resistance to degradation when exposed to UV light, accelerated weathering, elevated temperatures and fluids. In the present study the effect of addition of different percentages of fluoropolymers on the properties of mortar such as workability, compressive strength, flexural strength and permeability under different curing conditions i.e. dry and wet curing has been studied. Commercially available fluoropolymer based product Asahi-Guard E-series (AG-E400) was added in different quantities viz. 5, 10, 15 and 20 percent by weight of cement in cement mortar. On addition on fluoropolymers in the mortar it has been observed that the workability of the mortar increase with increase in percentage of fluoropolymers in the mortar and on addition of 20 percent the workability increases to a limit that the flow of mortar increases beyond the limits of flow table. Other properties of the fluoropolymer modified mortar were studied keeping workability of the mortar constant by adjusting the water content in the mortar. From the results it has been observed that compressive strength and flexural strength of the fluoropolymer modified mortar, for both dry and wet curing conditions, decreases with addition of fluoropolymers upto 10 percent thereafter an increasing trend was observed. However, with the addition of the fluoropolymers the permeability of the mortar decreases and this decrease is much more under wet curing conditions as compared to dry curing conditions. From the experimental programme carried out it can be concluded that fluoropolymer modified mortar can be used as good waterproofing material without much loss in mechanical properties by selecting suitable quantity of fluoropolymer in mortar.