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Durability of portland, calcium aluminate cement, calcium sulfate mixed binder systems
Ternary binders with Portland Cement, Calcium Aluminate Cement and Calcium Sulfate contain ettringite as significant hydration product. Such products have shown good behaviour in the field. Nevertheless, due to the lack of published data on the performance of these systems, many questions are raised about their durability. In this framework, a study was launched to provide insights into how such ternary blends evolve in natural environments. Samples were placed at four natural weathering sites covering a wide range of climates (Florida, Germany, Norway and Japan). After 3 years of outdoor storage on these sites, the exposed samples showed excellent stability of their macroscopic properties (mechanical strengths, dimensional changes). A detailed investigation of their microstructure was made by scanning electron microscopy. This paper presents the key findings of this study, and discusses the hydration mechanisms involved. This study presents for the first time in depth investigations at both macroscale and microscale on materials in the ternary system PC/CAC/CS. These materials, with their specific compositions and according to the operating modes carried out in this program maintain their strength and integrity under natural exposure and in accelerated tests. The microstructure development of Portland-based ternary systems is different from plain Portland and depends on the PC/CAC and CAC/CS ratios. The characteristic features of these binders is the formation of supplementary ettringite finely intermixed in the hydrated matrix. The presence of ettringite in these dense simple mortars based on a ternary hydraulic binder does not detrimentally affect the performance in the studied environments. The samples exposed in the field will continue to be monitored to study their evolution at later ages. The validity of this result out of the scope of this study will also require to be investigated.
Durability of portland, calcium aluminate cement, calcium sulfate mixed binder systems
Ternary binders with Portland Cement, Calcium Aluminate Cement and Calcium Sulfate contain ettringite as significant hydration product. Such products have shown good behaviour in the field. Nevertheless, due to the lack of published data on the performance of these systems, many questions are raised about their durability. In this framework, a study was launched to provide insights into how such ternary blends evolve in natural environments. Samples were placed at four natural weathering sites covering a wide range of climates (Florida, Germany, Norway and Japan). After 3 years of outdoor storage on these sites, the exposed samples showed excellent stability of their macroscopic properties (mechanical strengths, dimensional changes). A detailed investigation of their microstructure was made by scanning electron microscopy. This paper presents the key findings of this study, and discusses the hydration mechanisms involved. This study presents for the first time in depth investigations at both macroscale and microscale on materials in the ternary system PC/CAC/CS. These materials, with their specific compositions and according to the operating modes carried out in this program maintain their strength and integrity under natural exposure and in accelerated tests. The microstructure development of Portland-based ternary systems is different from plain Portland and depends on the PC/CAC and CAC/CS ratios. The characteristic features of these binders is the formation of supplementary ettringite finely intermixed in the hydrated matrix. The presence of ettringite in these dense simple mortars based on a ternary hydraulic binder does not detrimentally affect the performance in the studied environments. The samples exposed in the field will continue to be monitored to study their evolution at later ages. The validity of this result out of the scope of this study will also require to be investigated.
Durability of portland, calcium aluminate cement, calcium sulfate mixed binder systems
Lamberet, S. (author) / Scrivener, K. (author) / Amathieu, L. (author)
2006
8 Seiten, 10 Bilder, 2 Tabellen, 9 Quellen
Conference paper
English