Journal Article10.1016/0958-9465(96)00017-0
Delayed ettringite formation — Processes and problems
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TL;DR: In this paper, the scope of the delayed ettringite formation (DEF) problem is reviewed and the controversy concerning basic DEF mechanism between proponents of homogeneous paste expansion and crystal pressure is explored.
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Abstract: The scope of the delayed ettringite formation (DEF) problem is reviewed. Based on the experience of the writer and others, DEF is to be expected in both steam cured and non-steam cured concrete. The microstructural details appear identical. The common association with alkalisilica reactions is explored, and explained in terms of both prior cracking providing space for ettringite and in terms of the reduction in alkali hydroxide concentration in the pore solution attendant on ASR. The controversy concerning basic DEF mechanism between proponents of ‘homogenous paste expansion’ and ‘crystal pressure’ is explored. In the writer's opinion the microstructural evidence is not compatible with homogeneous expansion, but is a distinct consequence of crystal pressure developed by ettringite. The thermodynamic analysis that limits expansive pressure in terms of the degree of supersaturation that can be supported may be applicable to ettringite in air voids, but is inapplicable to ettringite in cracks. Fracture mechanics considerations predict local stress concentrations at the crack tips that are many times those that can be generated in open spaces. An apparent example of such effects in opening up space between mica lamellae in steam cured concrete by ettringite deposition is provided.
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Citations
Delayed ettringite formation
TL;DR: In this article, chemical and microstructural aspects of delayed ettringite formation are reviewed, and the authors show that the rate and ultimate extent of expansion are influenced by factors of three types: chemistry, paste microstructure, which determines the stresses produced by its formation.
771
A state-of-the-art review on delayed ettringite attack on concrete
TL;DR: In this paper, the authors present a critical review of the sulphate attack related to ettringite formation and show that not necessarily any ettinite-related expansion is related to the sulfate attack.
453
Evaluation of ettringite and hydrocalumite formation for heavy metal immobilization: literature review and experimental study.
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Physical and microstructural aspects of sulfate attack on ordinary and limestone blended Portland cements
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Use of porous ceramic waste aggregates for internal curing of high-performance concrete
TL;DR: In this paper, the efficiency of internal wet curing provided by a new type of aggregate, "recycled waste porous ceramic coarse aggregates" (PCCA), was investigated with respect to measured physical and mechanical property development.
246
References
Formation and expansion of ettringite crystals
Deng Min,Tang Mingshu +1 more
TL;DR: In this paper, the formation and expansion of ettringite crystals are discussed on the basis of principles of physico-chemistry, and it is suggested that eittringite forms by a through-solution mechanism and that expansive force results from crystallization pressure as well as swelling pressure converted from the reduction of chemical potentials.
191
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Mechanisms of Chemical Degradation of Cement-based Systems
K.L. Scrivener,J.F. Young +1 more
- 17 Apr 1997
TL;DR: In this article, the main costs result from poor performance and the need for early repair, which results in the substantial shortening of the lives of conventional concrete structures, such as the storage of nuclear waste, where very long service lives are essential.
152
Mechanism of sulphate expansion I. Thermodynamic principle of crystallization pressure
Xie Ping,James J. Beaudoin +1 more
TL;DR: In this article, a new theory concerning sulphate expansion phenomena in cement and concrete systems is developed based on the principles of chemical-thermodynamics, and it suggests that sulfate expansion is a process in which chemical energy is being converted into mechanical work to overcome the cohesion of system.
146
Delayed ettringite formation: a microstructural and microanalytical study
Karen Scrivener,H. F. W. Taylor +1 more
TL;DR: In this article, the authors show that the expansion that can be associated with delayed ettringite formation is driven by processes occurring within the paste and not by the formation of ettricite at aggregate interfaces.
136
Mechanism of secondary ettringite formation in mortars and concretes subjected to heat treatment. concrete durability. katherine and bryant mather international conference, held at atlanta, georgia, usa, 27 april-may 1987
TL;DR: In this article, a series of parameters have been examined as to their influence on the durability of heat treated concretes, including the threshold temperature of damage, the so3 content of the cement, the humidity of storage, and the w/c.
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