Proposed design methods for high-strength epoxy-modified reinforced concrete beams

Abstract EN

In recent years, epoxy-modified concrete (EMC) has been used for reinforced concrete (RC) structures subjected to aggressive environmental actions, and in hot climate conditions.

The present paper is concerned with the development of semi-empirical design methods for high-strength epoxy-modified reinforced concrete (EMRC) beams in flexure and shear.

First, the flexural design approach is based on strain compatibility and equilibrium conditions for EMRC section in combination with suitable idealized compression and tension stress blocks.

The stress blocks were given by suitable empirical functions for the compressive and post-cracking strengths of EMC.

Such functions were derived in terms of basic strengths of non-epoxy concrete and epoxy weight ratio.

Secondly, the shear design approach was derived for predicting the ultimate shear strength of EMRC beams with or without stirrups.

An empirical relation was developed for predicting the concrete contribution to shear as a function of compressive strength, tension steel ratio, and shear span-to-depth ratio.

The stirrups contribution to shear is evaluated by the truss analogy.

The validation studies showed that there is a good agreement between the flexural and shear strengths for EMRC beams as predicted by the proposed design methods and the experimental results reported in the literature.

The comparative studies with ACI Code equations indicated that the predicted strengths of ACI were more conservative.

The computed strengths by the finite element method were close to the calculated strengths of proposed approaches.

The comparison between the predictions of flexural and shear strengths with numerous experimental results for normal-strength and high-strength epoxy and non-epoxy reinforced concrete beams was shown to validate and generalize the proposed design methods.