Michele Paradiso

Artificial Ageing of Mortar Prisms Reinforced through Steel, Glass and Organic Fibres

The process of ageing in construction materials is natural and expected, and the technologies to contrast and reverse any damage due to the passing of time are well known in the field of civil engineering. This is true for structures themselves as well as the reinforcement technologies such as, for example, fiber reinforcements (FRP or FRCM). In fact, studies [1,5] have brought attention early on to severe mechanical characteristic reduction caused by the ageing process of specific resin matrices used in composite reinforcement materials, or, even more perilous, their exposure to extreme conditions of temperature. In this project, the authors have set up an experimental campaign on mortar prisms reinforced with different types of fibers and subjected to cycles of ageing through heat exposure. This paper presents the results obtained by three point flexural testing performed at the Testing Laboratory of the University of Florence, comparing the results of the reinforced and aged prisms with those of the non-aged and non reinforced prisms, providing a precedent on how ageing influences the structural behavior of fibers and mortar.

Problems Related to the use of Fiber Reinforced Cementitious Materials as Strengthening of Masonry Members

This paper gives the results of a series of tests carried out on brick columns and panels reinforced with Fibre Reinforced Cementitious Materials. Steel and glass fibres were used, and cement and lime mortars were employed as the matrices. The issue of durability of reinforced masonry structures, that is the transformation from sole masonry structures to hybrid ones, was investigated. Six brickwork columns (three unreinforced and three reinforced) and eighteen solid brick panels were built and tested (two unreinforced, 16 reinforced with steel cords or glass fibre). Tests were carried out in laboratory, and the results enabled the determination of the compression strength of the masonry before and after the application of the reinforcement, and before and after environmental effects. The main goal of the durability testing was to verify whether the artificial ageing process hinders the resistance. At the end of the cycles, a first visual observation was performed in order to evaluate if superficial alterations took place, such as efflorescence or micro cracking due to the immersion in the sodium chloride (NaCl) solution. The aged reinforced specimens appear to have a losses that range from 4% to 25% of the ultimate load, depending on the type of reinforcement and mortar used, although scattering of results confirm the need of more extensive testing.