4 documents found, page 1 of 1
Influence of Mineral Additions in the Inhibition of Delayed Ettringite Formatio...
Silva, A.S.; Soares, D.; Matos, L.; Salta, M.; Divet, L.; Pavoine, A.; Candeias, A.; Mirao, J.The degradation of concrete structures caused by delayed ettringite formation (DEF) is a problem that affects many concrete structures worldwide [1]. This pathology is due to the formation of expansive ettringite inside the material and is very difficult to deal with, because presently there is no efficient method to repair concrete structures affected by DEF. Hence, there is an urgent need to find preventive m...
The Application of Fluorescence Microscopy and Scanning Electron Microscopy in ...
Matos, L.; Silva, A.S.; Soares, D.; Salta, M.; Mirao, J.; Candeias, A.The degradation of concrete structures caused by delayed ettringite formation (DEF) is a problem that nowadays affects many concrete structures worldwide. This pathology is due to the formation of an expansive compound – ettringite - inside the material. This is a hydrated calcium sulphoaluminate produced by the chemical reaction between sulphate ions, calcium hydroxide and alumina present in the Portland cemen...
Characterisation of roman mortars from the historical town of Mertola
Silva, A.S.; Ricardo, J.; Salta, M.; Adriano, P.; Mirao, J.; Candeias, A.E.Ancient mortars from two Mertola’s important Roman monuments, the River Tower and the Cryptoportic, were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric and chemical analyses. The results show that all mortars are calcitic aerial lime mortars and that the aggregates are composed of quartzitic river sand and crushed schist. Samples from the River Tower and ...
Emprego de adições minerais para mitigação de reacções expansivas internas
Soares, D.; Santos SIlva, A.; Matos, L.; Salta, M.; Gonçalves, A.; Bettencourt Ribeiro, A.; Candeias, A.; Labrincha, J.; Ferreira, V.; Mirao, J.A degradação de estruturas de betão causada pela formação de etringite retardada (DEF, do inglês Delayed Ettringite Formation) é um problema que actualmente afecta estruturas de betão em todo o mundo. Esta anomalia é devida à formação de etringite, um composto que resulta da hidratação do cimento e que em determinadas condições se torna expansivo levando à fissuração do betão. Esta degradação é muitas vezes dif...