Mechanical properties of fluoropolymer modified mortar

Abstract

In past lot of experimental studies were carried out on polymer modified cement (PMC) mortar and concrete using polymers such as SBR, acrylic, VAE and integral water proofing 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, Split tensile strength at the age of 28 days and permeability & sorptivity at the age of 28 days under different curing conditions i.e.1 day wet 27 day dry & 7 day wet 21 day dry has been studied. The SEM and XRD analysis has been carried out to inestigate the results.The fluoropolymer was added in different quantities viz. 10, 20 and 30 percent by weight of cement in cement mortar. On addition of fluoropolymer in the mortar it has been observed that for a constant flow value the water cement ratio decreases as the addition of flouropolymer in the mortar is increased from 10-30 percent by weight of cement. 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 split tensile strength of the fluoropolymer modified mortar, for both 1 day wet 27 day dry & 7 day wet 21 day dry curing conditions, decreases with addition of fluoropolymers upto 10 percent thereafter an increasing trend was observed. However, with the addition of the fluoropolymer both the permeability and sorptivity of the mortar decreases and this decrease in much more under 7 day wet 21 day 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.