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- Cement-based grouts for masonry consolidation with high content of limestone filler, metakaolin, glass powder and ceramic wastePublication . Nepomuceno, Miguel C. S.; Bernardo, Luís; Oliveira, Luiz Pereira de; Timóteo, Rúben de OliveiraThis article reports an experimental research on the influence of high-volume mineral additions on the rheological, physical and mechanical properties of cement-based grout for stone masonry structures consolidation. Binary grout mixtures were produced by replacing 50% weight of cement by limestone filler, metakaolin, glass powder and ceramic waste. Grout flow properties, rheological parameters, bleeding water, bulk density and injectability were evaluated. Grout physical and mechanical properties were also tested. New methodology previously used in mortars was applied to interpret flow behaviour. Results showed that a high-volume mineral addition in cement-based grout is compatible with the required fresh and hardened properties.
- Effect of particle size distribution and calcium aluminate cement on the rheological behaviour of all-alumina refractory castablesPublication . Silva, Abílio P.; Segadães, A M; Pinto, Deesy G.; Oliveira, Luiz A.; Devezas, TessalenoPrevious works based on statistical design of experiments (DoE) defined a model all-alumina self-flow refractory castable (SFRC) with optimized particle size distribution for simultaneous high flowability index (FI) and superior post-sintering performance. This work compares the SFRC rheological behaviour and setting time with those of alternative all-alumina castables with different Andreasen aggregate particle size distribution modulus, and of the equivalent castables containing calcium aluminate cement. The model castable showed Bingham behaviour with low yield stress, viscosity and thixotropy, guaranteeing easier casting and less wear in the casting and/or projection equipment. However, as the coarse particle fraction increases, the castable flow tends to be non-linear and changes from Bingham to Herschel–Bulkley. The cement containing castables quickly loose flowability despite the applied shear. This work confirmed previous conclusions based on FI measurements and demonstrates the adequacy of the use of FI values in the calculation of FI response surface by DoE.