Degradation of building materials is an important phenomenon influencing their design and utilization. Mineral-based polymer-mortar composites (PMC) are often used as inexpensive promising materials to prevent the deterioration of constructions or remedy various reinforced concrete structures and they are used as materials for energy efficiency in buildings. In repair applications, polymer addition allows improving the adhesion properties of materials used in coating. With the intention of improving the sustainability of these composites, the influence of latex polymer and supplementary cementitious materials (natural pozzolan and silica fume) additions on the characteristics of these composites was investigated in aggressive media, such as acids. Mortars made with local pozzolanic mineral admixtures, obtained by substituting cement by different proportions of polymer (0, 5, 7.5, 10, 12.5 and 15%) were conserved in acidic solutions for 56 days. The microstructural analysis of these mortars was performed, using the X-ray diffraction technique, after 56 days of exposure to acid attack. The obtained results enable to bring out the beneficial effect of adding a latex polymer and other pozzolanic additives into modified materials on resistance to acid attacks. So, these composite materials can be recommended as materials for energy efficiency in buildings.

The growing need for building material resources, and the requirements to preserve the environment, in a vision of sustainable development, has become necessary to study reinforcement techniques, using composite materials. Using local organic or inorganic materials in construction fields and public works is particularly important. Polymer mortar composites (PMC) are usually employed in the building industry as finishing materials, tile adhesive (mortar-adhesive) or façade coating. In repair applications, the addition of soluble polymer (latex) allows improving the adhesion properties of the materials used as coating. The use of mineral additives as partial substitutes for cement, in construction sites as well as in ready-to-use mortars, is an unknown practice in our country. For this reason, we thought it is crucial to study and assess the influence of these additions on the properties of cured composite. Supplementary cementitious materials (SCM) used in this study are silica fume and natural pozzolan, which necessarily need to be valorized.The present research work aims to use a specific experimental methodology that is able to identify the relationship between the degree of substitution by the mineral additives, the polymer and the modifications to the properties of fresh and hardened cement mixtures. Therefore, five PMC combinations were formulated from different percentages of additions, i.e. natural pozzolan (NP: 25%w), silica fume (Sf: 5%w) and polymer latex (P: 0, 5, 7.5, 10, 12.5 and 15%w). Their durability factors, such as the porosity accessible to water and capillary absorption rate (sorptivity), were characterized, at different maturities. An attempt was also made to determine the thermal coefficients. The results obtained were compared with those of the reference mortars, made with Portland cement (CEMI). They showed that the decrease in porosity, sorptivity and thermal conductivity depends on the pair “SCMs/polymer”. But overall, the addition of polymer latex and pozzolanic additions have a beneficial effect on the durability and thermal properties of the composite materials.

Crosslinked poly(vinylalcohol) (PVA) hydrogel composites based on algerian hydrophilic natural Na-montmorillonite (Na-MMT) nanoclay named Maghnite-Na (Mag-Na) were prepared in aqueous media, without utilization of chemical crosslinking agents, by repeated cycles of freezing and thawing. The morphology of hydrogel composites and their swelling in water at different amount of Mag-Na were investigated. The characterization of obtained hydrogel composites by X-ray diffraction (XRD) showed a remarkable increase of the basal distance of Mag-Na in PVA hydrogels. Therefore, Intercalated and exfoliated morphology was observed for prepared composites hydrogels of PVA. The infra-red (FTIR) characterization results showed that some interactions have been developed between the hydroxyl groups of PVA chains and Mag-Na in composite hydrogels. Introducing Mag-Na into PVA hydrogel affected their swelling. Increased amount of Mag-Na decreased the equilibrium degree of swelling and equilibrium water content.

Nowadays, the major concern of professionals in the field of building materials is to improve the properties induced by the addition of different additives (polymers) and mineral additions (Supplementary Cement Materials SCMs) and to eventually adapt them to a particular application. This race towards performance has resulted in mortar formulations that are increasingly complex and rich in diversified additions. This is an industry-friendly practice since it generally yields a mortar modified by the combination of a polymer and SCMs, at low cost and low environmental impact, with an improved sustainability in the long term. In order to improve the durability of SCM-modified repair mortars, it seemed interesting to evaluate the influence of adding the styrene polyacrylic (SPA) Latex on the properties of these mortars when exposed to aggressive media such as acids. Composite mortars based on pozzolanic mineral additions, containing different levels of 0.5%, 1% and 2%w latex, were stored in acid solutions, for various periods of immersion. The analysis of the microstructure of these mortars, after exposure to acid attack, was carried out by FTIR spectroscopy. The results obtained allowed to demonstrate the beneficial effect of adding the SPA polymer and the pozzolanic additions to the modified materials and to show their improved resistance to acid attacks, such as HNO3 and H3PO4 solutions at 8%. The best durability properties of the mortars modified by the combination of the polymer and the additional cementitious materials observed in this study indicate a longer service life of the repaired structure when using this type of Latex-modified repair materials.

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