Performance of a Fly Ash Geopolymeric Mortar for Coating of Ordinary Portland Cement Concrete Exposed to Harsh Chemical Environments

Abstract

Premature degradation of ordinary Portland cement (OPC) concrete infrastructures is a current and serious problem with overwhelming costs amounting to several trillion dollars. The use of concrete surface treatments with waterproofing materials to prevent the access of aggressive substances is an important way of enhancing concrete durability. The most common surface treatments use polymeric resins based on epoxy, silicone (siloxane), acrylics, polyurethanes or polymethacrylate. However, epoxy resins have low resistance to ultraviolet radiation while polyurethanes are sensitive to high alkalinity environments. Geopolymers constitute a group of materials with high resistance to chemical attack that could also be used for coating of concrete infrastructures exposed to harsh chemical environments.This article presents results of an experimental investigation on the resistance to chemical attack (by sulfuric and nitric acid) of several materials: OPC concrete, high performance concrete (HPC), epoxy resin, acrylic painting and a fly ash based geopolymeric mortar. Two types of acids, each with high concentrations of 10%, 20% and 30%, were used to simulate long term degradation by chemical attack. The results show that the epoxy resin had the best resistance to chemical attack, irrespective of the acid type and acid concentration.

A Review on the Durability of Alkali-Activated Fly Ash/Slag Systems: Advances, Issues, and Perspectives

“…133 Recently, Tahri et al investigated the resistance to chemical attack (by sulfuric and nitric acid) of fly ash geopolymers for coating portland cement concrete. 134 It has been found that the fly ash geopolymeric mortar shows a good performance for sulfuric acid concentrations of both 10% and 20%. Even for a sulfuric acid concentration of 30%, this mortar shows good acid resistance for immersion for 14 days.…”

Effect of the calcinations temperatures of phosphate washing waste on the structural and mechanical properties of geopolymeric mortar

“…This material is inorganic polymer with lower CO 2 footprint. It is produced from a large number of natural minerals [56,57] or industrial waste [12][13][14][15]18,25,33,56,58] activated by an alkaline solution at ambient or slightly high temperature. It presents sometimes problems of cost and durability [59].…”