Early Age Restrained Strains and Self-Stresses of the Expansive Concrete Core in the Symmetrical Plane Restrained Condition

Kravchenko V.

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https://doi.org/10.35579/2076-6033-2019-11-03

ABSTRACT

The expansive concrete is used in the reinforced concrete structures to shrinkage compensating. Most efficiently its application in the Concrete Filled Steel Tubes (CFST), in which the expansive concrete can’t only compensate basic shrinkage of the filled CFST to effectively prevent separation structure but also induce self-stresses in the concrete core to keep it under in-plane biaxial compression before applying load.

The practical design of the CFST structures requires accurate estimation of restrained strain and stress in the expansive concrete core during the early age of curing. Currently, phenomenological models for the estimation of concrete strains are commonly used. At the same time, there are models which based on the principles and assumptions of the elasticity theory that have advantages over phenomenological models. Major disadvantage of these models is that they consider the development of concrete strains, taking into account only its elastic behavior, which predetermines their low accuracy.

In this article, the stress-strain development model for the restrained expansion strains and self-stresses estimation of expansive concrete core, taking into account the relaxation stresses due elastic and plastic deformation under both internal (aggregate) and external (steel shell) restrained conditions and a cumulative force induced by these restrains, what allows to determine more accuracy values is presented.

Keywords: cement paste, free expansion strains, restrained conditions, relaxation stresses, cumulative force, estimation model.

For citation: Kravchenko V. Early Age Restrained Strains and Self-Stresses of the Expansive Concrete Core in the Symmetrical Plane Restrained Condition. Contemporary Issues of Concrete and Reinforced Concrete: Collected Research Papers. Minsk. Institute BelNIIS. Vol. 11. 2019. pp. 36–50.

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ISSN 2664-567X (Online)
ISSN 2076-6033 (Print)

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