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Ravindra Gettu

Bio: Ravindra Gettu is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Portland cement & Cement. The author has an hindex of 28, co-authored 151 publications receiving 3475 citations. Previous affiliations of Ravindra Gettu include Structural Engineering Research Centre & Northwestern University.


Papers
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Journal ArticleDOI
TL;DR: Vandewalle, L., Nemegeer, D., Balazs, L, Barros, J., Bartos, P., Banthia, N., Criswell, M., Denarie, E., Di Prisco, M, Falkner, H., Gettu, R., Gopalaratnam, V., Groth, P, Hausler, V, Kooiman, A., Kovler, K., Massicotte, B., Mindess, S., Reinhardt, H, Rossi, P. as mentioned in this paper, Sch
Abstract: General information Publication status: Published Organisations: Section for Structural Engineering, Department of Civil Engineering Contributors: Vandewalle, L., Nemegeer, D., Balazs, L., Barr, B., Barros, J., Bartos, P., Banthia, N., Criswell, M., Denarie, E., Di Prisco, M., Falkner, H., Gettu, R., Gopalaratnam, V., Groth, P., Hausler, V., Kooiman, A., Kovler, K., Massicotte, B., Mindess, S., Reinhardt, H., Rossi, P., Schaerlaekens, S., Schumacher, P., Schnutgen, B., Shah, S., Skarendahl, A., Stang, H., Stroeven, P., Swamy, R., Tatnall, P., Teutsch, M., Walraven, J. Pages: 560-567 Publication date: 2003 Peer-reviewed: Yes

632 citations

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TL;DR: Sfer et al. as mentioned in this paper proposed a method to solve the problem by using the Sfer algorithm, which can be found at the Facultad de Ciencias Exactas and Tecnologia; Argentina
Abstract: Fil: Sfer, Domingo. Universidad Nacional de Tucuman. Facultad de Ciencias Exactas y Tecnologia; Argentina

261 citations

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TL;DR: In this paper, the potential of Limestone Calcined Clay Cement (LC3) for use in structural concrete in comparison with Ordinary Portland Cement and fly ash based blended cement (FA30) was described.

235 citations

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TL;DR: In this article, a review of the available methods of characterizing the flexural toughness of fiber reinforced concretes (FRCs) is presented, along with guidelines from standards institutions and other professional agencies in North America, Europe and Japan.
Abstract: The article comprises two parts. The first part presents a summary of the available methods of characterizing the flexural toughness of fiber reinforced concretes (FRC), with a review of most of the toughness standards and guidelines from standards institutions and other professional agencies in North America, Europe and Japan. Also reviewed are other significant proposals available in the published literature. The second part of the article includes a discussion of the merits and drawbacks of these measures. Other related issues discussed include: the fundamental significance, problems with regard to experimental measurements and the potential for practical design implementation of a toughness measure.

169 citations

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TL;DR: In this article, an experimental study of the fracture of concrete at constant CMOD rates with time to peak loads ranging from about 1 sec to 3 days (over five orders of magnitude).
Abstract: Reports an experimental study of the fracture of concrete at \"arious crack mouth opening displacement (CMOD) rates with time to peak loads ranging from about 1 sec to 3 days (over five orders of magnitude). Tests were conducted on three-point bend specimens of three sizes in the ratio 1:2:4. Quasi-elastic fracture analysis, based on the effective modulus jrom creep theory, is used to evaluate the results according to the size effect method. The fracture toughness is found to decrease in agreement with the trend known for the dynamic range. The effective length of the fracture process zone is found to decrease with increasing rate, which implies increasing brittleness and a shift toward linear elastic fracture mechanics behavior for slow loading. Load relaxation at constant CMOD in the prepeak and post-peak stages of fracture tests was also investigated. The response tends to a straight line in the logarithm of elapsed time, and the post-peak relaxation is nearly twice as strong as the linear viscoelastic relaxation of unnotched specimens, The difference between these two relaxations must be caused by time-dependent processes in the fracture zone. The results reveal that in concrete there is a strong interaction between fracture and creep, which might cause the load-carrying capacity of structures with cracks to decrease significantly with load duration. However, extrapolations to loads beyond several days of duration would be speculative.

168 citations


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TL;DR: In this paper, a modified regularized formulation of the Ambrosio-Tortorelli type was proposed to avoid crack interpenetration and predicts asymmetric results in traction and in compression.
Abstract: This paper presents a modified regularized formulation of the Ambrosio–Tortorelli type to introduce the crack non-interpenetration condition in the variational approach to fracture mechanics proposed by Francfort and Marigo [1998. Revisiting brittle fracture as an energy minimization problem. J. Mech. Phys. Solids 46 (8), 1319–1342]. We focus on the linear elastic case where the contact condition appears as a local unilateral constraint on the displacement jump at the crack surfaces. The regularized model is obtained by splitting the strain energy in a spherical and a deviatoric parts and accounting for the sign of the local volume change. The numerical implementation is based on a standard finite element discretization and on the adaptation of an alternate minimization algorithm used in previous works. The new regularization avoids crack interpenetration and predicts asymmetric results in traction and in compression. Even though we do not exhibit any gamma-convergence proof toward the desired limit behavior, we illustrate through several numerical case studies the pertinence of the new model in comparison to other approaches.

964 citations

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TL;DR: In this paper, the main fields of application of FRC composites are examined and future perspectives discussed, and some attention is paid to computation methods and composite materials' design approaches.

710 citations

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TL;DR: A review of the advances in knowledge provided by research in these areas can be found in this paper, emphasizing the impact of the research on the field and emphasizing the benefits of these advances.

614 citations

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TL;DR: In this article, potential-based models have been evaluated for mixed-mode cohesive fracture, and it is shown that these models lead to positive stiffness under certain separation paths, contrary to general cohesive fracture phenomena wherein the increase of separation generally results in the decrease of failure resistance across the fracture surface.
Abstract: One of the fundamental aspects in cohesive zone modeling is the definition of the traction-separation relationship across fracture surfaces, which approximates the nonlinear fracture process. Cohesive traction-separation relationships may be classified as either nonpotential-based models or potential-based models. Potential-based models are of special interest in the present review article. Several potential-based models display limitations, especially for mixed-mode problems, because of the boundary conditions associated with cohesive fracture. In addition, this paper shows that most effective displacement-based models can be formulated under a single framework. These models lead to positive stiffness under certain separation paths, contrary to general cohesive fracture phenomena wherein the increase of separation generally results in the decrease of failure resistance across the fracture surface (i.e., negative stiffness). To this end, the constitutive relationship of mixed-mode cohesive fracture should be selected with great caution.

555 citations

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TL;DR: In this paper, a review and categorization of a variety of tensile test setups used by other researchers and presents a revised tensile set up tailored to obtain reliable results with minimal preparation effort.
Abstract: Enhanced matrix packing density and tailored fiber-to-matrix interface bond properties have led to the recent development of ultra-high performance fiber reinforced concrete (UHP-FRC) with improved material tensile performance in terms of strength, ductility and energy absorption capacity. The objective of this research is to experimentally investigate and analyze the uniaxial tensile behavior of the new material. The paper reviews and categorizes a variety of tensile test setups used by other researchers and presents a revised tensile set up tailored to obtain reliable results with minimal preparation effort. The experimental investigation considers three types of steel fibers, each in three different volume fractions. Elastic, strain hardening and softening tensile parameters, such as first cracking stress and strain, elastic and strain hardening modulus, composite strength and energy dissipation capacity, of the UHP-FRCs are characterized, analyzed and linked to the crack pattern observed by microscopic analysis. Models are proposed for representing the tensile stress–strain response of the material.

542 citations