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Strengthening and repairing existing reinforced concrete structures is often more economical and sustainable than rebuilding them. The most commonly used technique, externally bonded Carbon Fibre Reinforced Polymers (CFRP), does not answer the need for a temperature resistant, fire safe and economical solution. High performance glass fibre Textile Reinforced Cements (TRC) can offer an answer to these drawbacks. A validation of this TRC technique against the existing one of CFRP is still needed. The Digital Image Correlation (DIC) and Acoustic Emission (AE) measuring techniques are applied to monitor the bending, cracking and failure behaviour of a reference beam, a beam with CFRP external reinforcement and a precracked and non-precracked TRC external reinforced beam. Fourpoint bending tests indicate the successful complementary use of DIC and AE and prove that TRC as an external reinforcement for concrete beams actually works.

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This work aims to study an aluminosilicate phosphate cementitious matrix. The cementitious matrix was studied on paste samples. The synthesis of metakaolinite phosphate cement (MKPC) was investigated using calorimetric techniques. A systematic study was performed by emphasizing a broad range of Al/P molar ratios, covering the different behavior of the material to the extremes, as well as the optimum composition. X-ray diffraction and scanning electron microscopy revealed that the final structure was mainly an amorphous network, albeit with some non-reacted phases. The compressive strength was studied on mortars using a cement/sand ratio of 1:3. MKPC specimens with Al/P ratios close to 1/1 showed optimal behavior. MKPCs with Al/P ratios above 1/1 were characterized by high porosity and low strength, whereas MKPCs with Al/P < 1 contained an excess of phosphates. The influence of the Al/P molar ratio on compressive strength was also studied, reaching a maximum of 68 MPa for the optimum composition. Based on the results, MKPC may be a promising candidate for construction purposes.

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