Effect of gypsum content on sulfoaluminate mortars stability

Desbois, Tiffany; Pavoine, Alexandre; Platret, Gérard; Feraille, Adélaïde; Alaoui, Amina

doi:10.3166/ejece.14.579-597

Cited by 2 publications

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“…Two main mechanisms of expansion due to ettringite formation have been proposed in the past which are based on “the crystal growth” and “the swelling” theories . Various factors such as CŜ/C 4 A 3 Ŝ ratio, presence of lime, w/cm ratio, particle size of C 4 A 3 Ŝ, temperature, and curing condition can influence the expansion characteristics of CSA cements. Although there have been a significant number of studies on hydration and microstructure development of CSA cement, studies related to blend of OPC and CSA cements are still limited .…”

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confidence: 99%

Influence of Calcium Sulfoaluminate (CSA) Cement Content on Expansion and Hydration Behavior of Various Ordinary Portland Cement‐CSA Blends

2015

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Calcium sulfoaluminate (CSA) cements have lower carbon footprint than that of portland cement, which makes them a suitable alternative as a sustainable cementitious binder. Early‐age expansion of CSA cements can be exploited to induce compressive stress in restrained concrete which can later counteract tensile stress developed during drying shrinkage, thus enhancing the resistance against shrinkage cracking. However, a proper understanding of the expansion behavior is critical to eliminate any risk related to expansion‐induced cracking. This study examines the expansion and hydration characteristics of various ordinary portland cement (OPC)‐CSA blends. Early‐age expansion of paste samples was monitored. The increase in CSA cement content increased the extent of expansion. Samples having the highest CSA content (30% by mass) exhibited excessive expansion which led to their cracking. Quantitative X‐ray diffraction, pore solution extraction, porosity, tensile strength, and dynamic modulus tests were performed to monitor the physico‐chemical changes in OPC‐CSA blends. It was shown that the ettringite supersaturation in the investigated systems gave rise to the crystallization stress, responsible for the expansion. Thermodynamic models enabled a reasonable prediction of tensile failure, particularly in the blends with the higher CSA content.

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