Semester

Summer

Date of Graduation

2006

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Samir Shoukry

Committee Co-Chair

Gergis William

Abstract

Previous research has shown that thermal stresses developed in concrete pavements due to daily and seasonal temperature variations may be larger than those induced due to traffic loading. Dowel bars that are used for load transfer at the transverse joints of concrete pavements introduce high stresses at their interfaces with concrete leading to various forms of transverse joint distress. To solve this problem, Shoukry et al. (2001) developed an alternative design of dowel bars called "Shok Bar" that was installed by Shoukry and his team in a concrete pavement section placed at the parking lot of WVDOT Maintenance Shop at Goshen Road, WV. The built section was instrumented to experimentally measure the strains developed in concrete slabs.;In the present work, the measured behavior of slabs fitted with Shok bars is studied and compared with that measured for slabs fitted with regular dowel bars. The effect of slab-base friction on the expansion and contraction of concrete slabs is studied. The thermal stresses known to cause the top-down transverse cracking at the mid-slab were investigated. The results indicate that the new dowel bar design reduces the concrete slab strains especially during the initial stages of concrete setting. The Shok bars reduce permanent residual strain in the slab, lower the axial forces in the dowels considerably and help in relieving curling stresses in the pavement. The measured data show that slabs fitted with Shok bars have symmetrical joint opening compared with those slabs that were fitted with regular dowel bars.;In this study the thermal diffusivity theory was used to develop a method to calculate the temperature and the thermally induced strain at different depths through the slab thickness given the time history of weather parameters: air temperature, solar radiation, relative humidity, and wind velocity. While previous research efforts were limited to sunny and clear days, this method is capable of calculating the slab temperature for a 24 hour period and also for a sequence of days including days with light rain and cloud cover. The effects of snow cover on the slab and heavy rainfall on the method have been discussed. Equations for the strains developed at the slab top and bottom were presented. The temperatures calculated by the method were compared with the values measured from the test slabs. The results from the proposed model were found to be in reasonable agreement with the experimentally measured data from the slabs.

Download

Share

COinS