Detachment analysis of dehumidified repair mortars applied to historical masonry walls

An innovative laboratory procedure for the pre-qualification of repair mortars is described. The tested mortars are suitable for use with new dehumidified plasters applied to historical masonry walls. Long-term plaster detachment frequently occurs because of the mechanical incompatibility of mortar. The procedure consists of the application of static loads to mixed stone block-mortar specimens with particular characteristics, in terms of geometry and adhesion at the interface. A numerical simulation based on the cohesive crack model was used to follow the experimental data, in order to describe the evolutionary phenomenon of detachment as a function of a small number of parameters. The methodology is currently being used at Sacro Monte di Varallo Special Natural Reserve (UNESCO heritage site) in Piedmont (Italy

An overview of the flexural post-cracking behavior of steel fiber reinforced concrete

This paper provides a general overview of recent developments in the study of the flexural post-cracking behavior of steel fiber reinforced concrete (SFRC). The results of three-point-bending tests (3PBTs) performed at the University of Brescia during the last lustrum were collected in a broad database consisting of 81 series for a total amount of 528 beams. Several experimental parameters were investigated: strength of concrete matrix, fiber dosage, fiber aspect ratio, fiber filament tensile strength, as well as fiber orientation. The latter was deeply studied by means of image analysis of cut cross sections. The results, discussed in terms of post-cracking flexural residual strengths, highlight that all the parameters studied contribute to the post-cracking performances exhibited by SFRCs