Empirical relationships between compressive and flexural strength of concrete containing recycled asphalt material for pavement applications using different specimen configurations

C.R Marín-Uribe,R Navarro-Gaete

doi:10.3989/mc.2021.11520

C.R Marín-Uribe, R Navarro-Gaete

Open Access

https://doi.org/10.3989/mc.2021.11520

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Abstract

The flexural strength of pavement concrete is generally deduced by testing beams or by applying empirical equations. In this investigation, concrete mixtures were manufactured, incorporating 0, 20, 50 and 100% Reclaimed Asphalt Pavement (RAP), by weight, as a replacement for natural aggregates. The compressive strength was measured using cubic specimens and the flexural strength was measured for three types of specimens; beam, semicircular (SCB) and modified beam. This study proposes logarithmic and power equations that allow the estimation of the flexural strength of a concrete mix that incorporates RAP as a function of its compressive strength. Linear or power models are proposed to predict beam flexural strength from SCB specimens and a logarithmic model for modified beam specimens. Statistical analyses show that the proposed prediction models can be considered sufficiently accurate and their use is justified.

Highlights

The flexural strength of pavement concrete is generally deduced by testing beams or by applying empirical equations
The results show a systematic reduction in the compressive strength of concrete mixtures made with Reclaimed Asphalt Pavement (RAP), compared to the control mix; this is consistent with the literature [13, 17, 37,38,39]
The reduction in strength could be due to the asphalt layer around the RAP particles being softer than the concrete and aggregate matrix

Summary

Introduction

The flexural strength of pavement concrete is generally deduced by testing beams or by applying empirical equations In this investigation, concrete mixtures were manufactured, incorporating 0, 20, 50 and 100% Reclaimed Asphalt Pavement (RAP), by weight, as a replacement for natural aggregates. Flexural strength is a measure of the tensile strength of a concrete and is expressed in terms of the Modulus of Rupture (MOR) This parameter is used in structural design [1], quality control and acceptance of pavements [2], which is determined by the standard methods given in ASTM C78 (third-point loading) or ASTM C293 (center-point loading) using a standardized 150 x 150 x 550 mm beam. In Chile, the Ministry of Public Works limited the incorporation of RAP for HMA to 20% replacement [16]

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