Some aspects and mechanisms of sulphate attack

• Autorzy: Piasta W. , Marczewska J. , Jaworska M.

Warianty tytułu

PL

Wybrane aspekty i mechanizmy korozji siarczanowej

• Języki publikacji: EN PL

Abstrakty

EN

Consideration of the concrete durability should take into account sulphate attack which may be significantly various. The destruction of concrete under sulphate attack is particularly related to expansion, however, the dissolution of cement matrix may by considerable. The way of destruction is dependent on the type of salt, its cation and solution pH. The most reactive phases of cement paste are alumunoferrite hydrate phases (AFm) and calcium hydroxide. The expansion is directly connected with formation of gypsum and ettringite. The ultimate product of total destruction of concrete is gypsum. Mechanism of sulphate attack is a subject of discussion and hypotheses. The test results of expansion of mortar immersed in 5% Na₂SO₄ and SEM analysis indicate that ettrinite formed in air pores may not affect the value of the expansion. Ettringite formation inside small pores of the microstructure (eg C-S-H) can cause expansive force and destruction of mortars.

Słowa kluczowe

EN

sulphate attack; cement paste; mortar; SEM; air entrainment; ettringit

PL

agresja siarczanowa; zaczyn cementowy; zaprawa; elektronowy mikroskop skaningowy; napowietrzenie; ettringit

• Wydawca: Wydawnictwo Politechniki Świętokrzyskiej
• Czasopismo: Structure and Environment
• Rocznik: 2014
• Tom: Vol. 6, no. 3
• Strony: 19--24
• Opis fizyczny: Bibliogr. 10 poz., rys.

Twórcy

autor

Piasta W.

• Kielce University of Technology

autor

Marczewska J.

• Kielce University of Technology

autor

Jaworska M.

• Kielce University of Technology

Bibliografia

• [1] Brown W, Taylor H.: The role of ettringite in external sulfate attack, Materials Science of Concrete: Sulfate Attack Mechanisms, The American Ceramic Society, 1999, pp. 73-98.
• [2] Eurocode 2: Design of concrete structures. European Standard EN 1992-1-1 December 2004.
• [3] Kurowski W.: Chemia cementu i betonu, Polski Cement, Kraków 2010.
• [4] Lafuma H.: Theory of the expansion of cement, Revue Mater. Const. Vol. 243, 1970, p. 441.
• [5] Mehta P.K.: Mechanism of sulfate attack on portland cement concrete- Another look, CCR, Vol. 13, 1983.
• [6] Neville A.M.: Właściwości betonu. Stowarzyszenie Producentów Cementu, Kraków 2012.
• [7] Piasta W.: Korozja siarczanowa betonu pod obciążeniem długotrwałym, Politechnika Świętokrzyska, Kielce 2000.
• [8] Piasta W., Marczewska J., Jaworska M.: Wpływ napowietrzenia na odporność siarczanową zapraw z cementów portlandzkich, KONTRA, Szczyrk 2014.
• [9] Ping X., Beaudoin J.: Mechanism of sulphate expansion I. Thermodynamic principle of crystallization pressure, Cement Concrete Research 22, 1992, pp. 631-640.
• [10] Yu Ch., Sun W., Scrivener K.: Mechanism of expansion of mortars immersed in sodium sulfate solutions, Cement and Concrete Research, 2012.