W. Tahri

Cost efficiency and resistance to chemical attack of a fly ash geopolymeric mortar versus epoxy resin and acrylic paint coatings

This article presents results of an experimental investigation on the resistance to chemical attack (with sulphuric, hydrochloric and nitric acid) of several materials: OPC concrete, high-performance concrete, epoxy resin, acrylic painting and a fly ash-based geopolymeric mortar). Three types of acids with three high concentrations (10, 20 and 30%) were used to simulate long-term degradation. A cost analysis was also performed. The results show that the epoxy resin has the best resistance to chemical attack independently of the acid type and the acid concentration. However, the cost analysis shows that the epoxy resin-based solution is the least cost-efficient solution being 70% above the cost efficiency of the fly ash-based geopolymeric mortar.

Performance of alkali-activated mortars for the repair and strengthening of OPC concrete

Abstract Infrastructure rehabilitation represents a multitrillion dollar opportunity for the construction industry. In the United States alone, the rehabilitation needs are estimated to exceed 1.6 trillion dollars over the next five years. Since the majority of the existing infrastructure is concrete based, this means that concrete infrastructure rehabilitation is a hot issue. Besides, the sooner concrete deterioration is tackled, the lower are the rehabilitation costs. The majority of current commercial repair materials are not cost efficient and some even present both technical and worrying environmental limitations. This chapter provides a literature overview on concrete repair materials, highlighting current problems faced by them. The potential of alkali-activated mortars to overcome those limitations is analysed.

Performance on an Alkali-Activated Cement-Based Binder (AACB) for coating of an OPC infrastructure exposed to chemical attack: a case study

Premature degradation of ordinary Portland cement (OPC) concrete infrastructure 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 are not cost-efficient and have low resistance to ultraviolet radiation while polyurethanes have low resistance to chemical attack. This chapter presents results of an experimental investigation on the resistance to chemical attack (with sulfuric, hydrochloric, and nitric acid) of several materials: OPC concrete, high-performance concrete, epoxy resin, acrylic painting, and a fly ash–based geopolymeric mortar. Three types of acids with three high concentrations (10%, 20%, and 30%) were used to simulate long-term degradation. A cost analysis was also performed. The results show that the epoxy resin has the best resistance to chemical attack independently of the acid type and the acid concentration. However, the cost analysis shows that the epoxy resin–based solution is the least cost-efficient solution being 70% above the cost efficiency of the fly ash–based geopolymeric mortar.

Geopolymeric repair mortars based on a low reactive clay

Abstract This chapter discloses results of an investigation concerning the development of geopolymeric repair mortars based on a low reactive Tunisian clay. Geopolymeric mortars were studied for workability, compressive strength, adhesion, unrestrained shrinkage, and modulus of elasticity. Several concrete beams, rehabilitated with a metallic grid and geopolymeric mortars were also tested for flexural strength. The hydration products were studied using X-ray diffractograms (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR).

Produtos de hidratação em argamassas geopoliméricas à base de argila da Tunísia para reparação de estruturas de concreto

A reparacao de estruturas degradadas de concreto representa uma oportunidade para a industria da construcao mas tambem um desafio para a comunidade cientifica. O desenvolvimento de novas argamassas de reparacao constitui por isso uma importante area de investigacao. Os geopolimeros sao ligantes inovadores alternativos ao cimento Portland pelo que as argamassas a base destes materiais, geopolimericas, apresentam algumas potencialidades no campo da reparacao das estruturas de concreto. O presente artigo apresenta resultados de uma investigacao sobre o desenvolvimento de argamassas geopolimericas a base de uma argila da Tunisia sujeita a tratamento termico. E incluida uma analise da argila e tambem dos produtos de hidratacao da argamassa os quais apresentam fases geopolimericas tipicas.