PORE WATER TENSION IN FREEZING CONCRETE – THE REASON WHY AIR-ENTRAINMENT IMPROVES FREEZE-THAW DURABILITY

Author(s): Vesa Penttala
Paper category: Proceedings
Book title: Proceedings of CONSEC13 Seventh International Conference on Concrete under Severe Conditions - Environment and Loading Volume I
Editor(s): Z.J. Li, W. Sun, C.W. Miao, K.Sakai, O.E. Gjørv, N.Banthia
ISBN: 978-2-35158-124-7
e-ISBN: 978-2-35158-134-6
Publisher: RILEM Publications SARL
Publication year: 2013
Pages: 320-331
Total Pages: 961
Language : English

Abstract: The stresses generated into wet mortar or concrete and into pore water during freeze-thaw distress were studied theoretically and experimentally. Mechanical stability criterion was introduced by which the situation when ice can bulge from a frozen pore to the adjacent water filled capillary is separated from the situation when the tensile strength of ice is exceeded and a concave water-ice interphase is formed. The last mentioned situation occurs in air-entrained mortars and concretes and then ice cannot percolate from frozen pore through the adjacent water filled capillaries and no crystallization pressures can be generated. The theoretical results were corroborated by test results performed with mortar test specimen situated in a calorimeter. Surface strains of the mortar prisms were measured during the test. The pore water tension of the air-entrained and non-air-entrained mortars were calculated and compared with each other.

Online publication : 2013
Publication type : full_text
Public price (Euros) : 0.00