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Abstract: The simultaneous use of different types of fibers as reinforcement in cementitious matrix composites is typically motivated by the underlying principle of a multi-scale nature of the cracking processes in fiber reinforced cementitious composites. It has been hypothesized that while undergoing tensile deformations in the composite, the fibers with different geometrical and mechanical properties restrain the propagation and further development of cracking at different scales from the micro- to the macro-scale. The optimized design of the fiber reinforcing systems requires the objective assessment of the contribution of each type of fiber to the overall tensile response. Possible synergistic effects resulting from particular combinations of fibers need to be clearly identified. In the present study, the evaluation of the response of different fiber reinforced cementitious composite materials is carried out by assessing directly their tensile stress-crack opening behavior. The efficiency of hybrid fiber reinforcements and the multi-scale nature of cracking processes are discussed based on the experimental results obtained, as well as the micro-mechanisms underlying the contribution of different fibers to bridge cracks resulting from tensile loading. [Copyright &y& Elsevier]

Abstract: The process of designing Strain Hardening Cementitious Composites (SHCC) is driven by the need to achieve certain performance parameters in tension. These are typically the pseudo-strain hardening behavior and the ability to develop multiple cracks. The assessment of the tensile load-deformation behavior of these materials is therefore of great importance and is frequently carried out by characterizing the material tensile stress–strain behavior. In this paper an alternative approach to evaluate the tensile performance of SHCC is investigated. The behavior of the material in tension is studied at the level of a single crack. The derived tensile stress-crack opening behavior is utilized to analyze and compare the influence of various composite parameters on the resulting tensile behavior. The deformations occurring during tensile loading are furthermore examined using a digital image-based deformation analysis technique to gain detailed insight into the crack formation, propagation and opening phases. [Copyright &y& Elsevier]

This paper surveys different material combinations and applications in the field of mineral-based strengthening of concrete structures. Focus is placed on mechanical behavior on material and component levels in different cementitious composites; with the intention of systematically maping the applicable materials and material combinations for mineral-based strengthening. A comprehensive description of a particular strengthening system developed in Sweden and Denmark, denominated as Mineral based Composites (MBCs), together with tests from composite material properties to structural elements is given. From tests and survey it can be concluded that the use of mineral-based strengthening system can be effectively used to increase the load bearing capacity of the strengthened structure. The paper concludes with suggestions on further development in the field of mineral-based strengthening. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the monotonic and fatigue behavior of a link slab designed for a durable concrete bridge deck system. The requirements on the link slab in terms of material properties, dimensions, and reinforcement detailing are considered. Special focus is placed on the deflection capacity of the link slab and its fatigue performance. This paper discusses the choice of a fiber reinforced engineered cementitious composite (ECC) material based on the performance requirements of link slabs in the context of an integrated structure-material design scheme. Experimental results of monotonic and subsequent cyclic tests of full-scale ECC link slabs are compared with those of an ordinary reinforced concrete link slab. The mode of deformation will be discussed with particular emphasis on the development of crack widths, which is important for durability against steel reinforcement corrosion. The significant enhancements of deflection capacity and crack width control in ECC link slabs suggest that the use of ECC material can be effective in extending the service life of repaired bridge deck systems. [ABSTRACT FROM AUTHOR]

Presents an experimental study on the fundamental performances of a sprayed engineered cementitious composite in repair systems. Demonstration of the potential enhancement of durability of repaired infrastructures; Performance of uniaxial tensile and flexural tests; Evaluation of the repair performance.

The results of the second part of a comprehensive experimental program, aimed at investigating the behavior of masonry infilled reinforced concrete (RC) frames strengthened with fiber reinforced engineered cementitious composites (ECC) used as an overlay on the masonry wall, are presented in this paper. The proposed strengthening technique aims at increasing the lateral strength of infilled RC frames and maintaining the integrity of masonry infills during loading, which is an important seismic parameter for these elements. Material tests were conducted first for ECC in order to assess its distinctive mechanical properties such as tensile stress–strain behavior and multiple cracking. Thereafter, three 1/2 scaled one bay, one story RC specimens were constructed and tested under quasi-static lateral loading. The obtained results are presented and discussed in terms of the strength, stiffness, and the cumulative absorption capacity of the tested specimens. Furthermore, the obtained backbone curves are idealized and the drift limits usually considered in seismic design are specified. The obtained results indicate that the proposed ECC-strengthening technique can effectively increase the lateral strength and energy absorption capacity of the infilled frame, prevent brittle failure modes in the infill wall, and provide a reasonable system overstrength. [ABSTRACT FROM AUTHOR]