Effect of wetting–drying cycles on mode I and mode II fracture toughness of cement mortar and concrete. (April 2020)

• Record Type: Journal Article
• Authors: Dehestani, Arash; Hosseini, Mehdi; Taleb Beydokhti, Alireza
• Is Part Of: Theoretical and applied fracture mechanics. Volume 106(2020)
• Publication Date: 2020-04
• Subjects: Wetting–drying cycles -- Mode I and mode II fracture toughness -- Cement mortar -- Concrete -- Chevron notch; Fracture mechanics -- Periodicals; 620.1126
• DOI: 10.1016/j.tafmec.2019.102448
• Languages: English
• ISSNs: 0167-8442

Abstract

Highlights: Investigating the effect of the number of wetting-drying cycles on fracture toughness of concrete and cement mortar. Relationship between fracture toughness and the number of wetting-drying cycles. Relationship between effective porosity and the number of wetting-drying cycles. Abstract: Cement mortar and concrete are affected by wetting–drying cycles due to variable precipitation and evaporation rates and changes in the level of water reservoirs in most development projects such as dam construction projects. The alternating interaction of water with cement mortar and concrete affects mode I and mode II fracture toughness and accelerates their erosion rate. Hence, it is necessary to evaluate the effect of wetting–drying cycles on mode I and mode II fracture toughness. Cement mortar and concrete specimens were prepared for this purpose. The mode I and mode II fracture toughness were determined by conducting tests on centrally cracked Brazilian disc (CCBD) specimens. A chevron notch and a straight-through crack were created respectively in cement mortar and concrete specimens. The specimens were loaded after 0 (the specimen subject to no wetting-drying cycles), 1, 4, 8, 16 and 20 wetting–drying cycles. The mode I and mode II fracture toughness of cement mortar and concrete decreased with increasing the number of wetting–drying cycles. Porosity and paste volume (cement and water volume) were identified as the main factors reducing fracture toughness and fracture toughness reduction rate.