The alkali activation of alumino-silicate materials is a complex chemical process evolving dissolution of raw materials, transportation or orientation and polycondensation of the reaction products. Publications on the field of alkali-activated binders, state that this new material is likely to have high potential to become an alternative to Portland cement. While some authors state that the durability of these materials constitutes the most important advantage over Portland cement others argue that it's an unproven issue. This paper presents a review of the literature about the durability of alkali-activated binders. The subjects of this paper are resistance to acid attack, alkali-silica reaction, corrosion of steel reinforcement, resistance to high temperatures and to fire, resistance to freeze-thaw. Special attention is given to the case of efflorescences, an aspect that was received very little concern although it is a very important one.

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Reinforcement of cementitious materials with short fibers has been proved to be an economical and effective way to convert these brittle materials to ductile products. Many fibers with different geometries have been used as reinforcement materials. Fibers bonding to cementitious materials play an important role in mechanical performance of these composites. This article describes the performance of (homemade) fibers as reinforcement in cement-based materials by investigation on bonding characteristic of fiber to cement matrix. To this end, the fibers (glass, polypropylene, polyacrylonitrile (PAN), and high strength nylon 66 (N66)) are characterized using microscopy analysis, tensile strength, and alkali attack tests. The fibers embedded in the cement matrix, then, pulled-out to evaluate their bonding to cementitious materials. SEM analysis is used to study fiber/cement interfacial transition zone. The results show that PAN fibers have the advantages of preparing for cementitious reinforcement. It was found that the reinforcing efficiency of fibers-reinforced cementitious composites was strongly depending on interfacial contact area in fiber/matrix interface and chemical/physical properties of fibers.

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Non-agglomeration and dispersion of silica nanoparticles in polymers and their interfacial interactions to polymer matrix are the most important factors that influence nanocomposites performance. In this work, vinyltriethoxysilane (VTES) as a low VOC emission coupling agent was used for surface modification of silica nanoparticles to prepare better dispersion in nitrile rubber (NBR) and improve its interfacial interactions to silica nanoparticles. The results of X-ray photoelectron spectroscopy, thermogravimetric analysis and Fourier transform infra-red spectroscopy demonstrated successful attachment of VTES molecules on the surface of silica nanoparticles. Dispersion of the modified silica nanoparticles in NBR matrix was studied using field emission scanning electron microscopy and rubber process analysis. Results demonstrated that VTES significantly improved dispersion of nanoparticles in rubbery matrix. The bound rubber content showed that VTES effectively built a bridge between the silica nanoparticles and the rubber matrix that led to promising mechanical performances and strong interfacial interactions. Effect of nanoparticle content on the mechanical performances (static/dynamic) of the NBR was evaluated. It was found that higher modulus and reinforcement indices was obtained at 3 and 5 wt% of nanoparticles. Moreover, these composites had extremely low rolling resistance, the best wet skid resistance and the lowest Heat-Build up.