Mechanics of SFRC under tension, part I: analytical study

Abstract

This is the first of a two-part paper involving a fundamental study of mechanics of short-fibre-reinforced concrete under tension. The theory derived in this paper is validated in a second paper using experimental investigation. The composite material approach, which is based on micromechanics, is employed to describe the phenomenon in terms of constitutive properties of fibre, matrix, fibre-matrix interface and their proportioning. The tensile stressstrain behaviour of short-fibre-reinforced concrete is described with four distinct stages, namely the elastic stage, the stage of closed isolated crack development, and the stages of through-crack development both in the absence of fibre rupture and in the presence of fibre rupture. The analytical development does not require pre-assumed composite behaviour such as peak load, initial tangent modulus etc. The formulation is validated using experimental investigation, supplemented by the results of the available models in the existing literature. Given the extent of the study, it was decided to present the entire work in two parts. The general theoretical development is presented here in part I and the comparisons with test results are presented in the companion paper, as part II.

Mechanics of SFRC under tension, part II: experimental validation

“…The predictability of the analytical approach is also scrutinised for peak load, ultimate load deformation, ductility and so on. The general aspects of the formulations, with the necessary assumptions involved in the model, are provided in part I (Ghosh et al, 2010). In the present paper, the stress-strain results obtained from the analytical development are verified with detailed experimental investigations, considering a wide range of fibre lengths, diameters and volume fractions.…”

“…The objective of the experimental investigation is to supplement the stress-strain behaviour of the analytical development presented in part I (Ghosh et al, 2010). The size, shape and concentration of fibre adopted were selected on the basis of actual possible use in the field with special emphasis on the detailed comparison of the analytical results with the experimental data.…”

“…The tensile stress-strain behaviour of short-fibrereinforced concrete (SFRC) is studied in the precracking stage, the post-cracking stage with the stage of closed isolated crack development and the stage of through crack development, both in the absence and the presence of fibre rupture, are presented in the first part of the current study (Ghosh et al, 2010). Incremental strain steps based on a constitutive model are proposed to obtain the complete stress history.…”