Effects of dowel bars misalignment in jointed plain concrete pavements – A numerical analysis considering thermal differentials and bonded slab-base interface

Eric Ribeiro Da Silva,José Tadeu Balbo,Andréia Posser Cargnin

doi:10.1590/s1983-41952021000400014

Abstract

Abstract Joints in concrete pavements are built to allow slab volumetric variations avoiding random cracks. Moreover, as they are discontinuities, the use of dowel bars prevents loss of load transfer across joints. During bars installation or even concrete casting, misalignments and misallocations of those devices may occur, affecting the concrete pavement structural performance. This study explores the effects of such non-conformities in the positioning of dowel bars through numerical modeling, using the 3D finite element program EverFE2.25. For, numerical simulations, bending stresses in concrete slabs of a typical bus corridor were ascertained, varying misalignments types and magnitudes (vertical tilt and horizontal skew), base type (cemented and asphalt), slab/base interface bond conditions and concrete thermal differential. Results disclosed the contribution of using bonded base in reducing stresses, even when the dowels were severely misaligned while slabs were subjected to high thermal differentials.

Highlights

One of the most specific characteristics in concrete pavements is the presence of contraction joints, normally built to enable the concrete expansion and contraction during its cure and under severe weather conditions, avoiding the occurrence of random shrinkage cracks [1], [2].as joints create discontinuities in concrete pavements, their presence reduces the load transfer capacity, requiring, the introduction of a load transfer mechanism across these joints [3]
Thereby, the current study addresses the effects of dowel bars misalignment combined with positive thermal gradient, comprising the bond effect given at the slab/base interface, on the structural response of a jointed-plain concrete pavement (JPCP), through numerical simulations using the finite element method (FEM), accomplished by simulations applying EverFE 2.25 software [14]
When the concrete slab was unbounded to cement-treated base, for a thermal gradient of 20°C, the maximum stress was recorded at the top of the concrete slab; otherwise, for asphalt base unbounded to the concrete slab and thermal differential of 15°C and 20°C, the maximum flexural stresses were recorded at the middle of the concrete slab

Summary

INTRODUCTION

One of the most specific characteristics in concrete pavements is the presence of contraction joints, normally built to enable the concrete expansion and contraction during its cure and under severe weather conditions, avoiding the occurrence of random shrinkage cracks [1], [2]. Investigations on concrete pavements mechanical behavior employing the finite element method (FEM) have increasingly spread Most of these studies are concentrated on the load transfer efficiency analysis in concrete pavement joints with aligned dowel bars [13]. Thereby, the current study addresses the effects of dowel bars misalignment combined (horizontal skew and vertical tilt) with positive thermal gradient (mostly found in roads in tropical environments), comprising the bond effect given at the slab/base interface, on the structural response of a jointed-plain concrete pavement (JPCP), through numerical simulations using the FEM, accomplished by simulations applying EverFE 2.25 software [14]

Justification

NUMERICAL MODEL DESCRIPTION

Concrete pavement structure modeling

Dowel bars positioning at transverse joints

Analysis of dowel bars properly positioned

CONCLUSIONS