Spalling in Continuously Reinforced Concrete Pavement in Texas

Abstract

The performance of continuously reinforced concrete pavement (CRCP) in Texas has been quite satisfactory, primarily thanks to the continuous improvements in design and construction. However, severe spalling has been a major problem, and the Texas Department of Transportation (TxDOT) has sponsored several research projects since 1985 to identify solutions for this serious problem. Even though the research efforts were successful in identifying spalling mechanisms, developing a policy that TxDOT could easily implement has been a challenge. To develop a more practical solution to this problem, TxDOT initiated a research study, and the research efforts consisting of identifying CRCP projects with severe and no spalling, obtaining and conducting materials testing on concrete cores from those projects, analyzing the testing data, and performing theoretical analyses to validate the testing results. Among the material properties evaluated, the coefficient of thermal expansion (CTE) of concrete proved to have the best correlation with spalling. Detailed analyses of mechanistic behavior of concrete conducted with an object-oriented finite element program (OOF2) and commercial finite element program verified the reasonableness of the field-testing results. All concrete cores from CRCP with severe spalling had a CTE larger than 5.5 microstrains/°F, whereas no spalling was observed in concrete with a CTE less than that value. Based on this finding, TxDOT now requires the use of coarse aggregate that will produce concrete with a CTE of less than 5.5 microstrains/°F for CRCP construction. It is expected that this implementation will reduce the spalling in CRCP substantially.

Investigation into the Impact of Humidity on Early Age Cement Concrete Pavement Behavior in Hot and Humid Regions

“…In the Equation (1), ∂h/∂t is the total relative humidity change in the panel, ∂h d /∂t is the humidity change due to diffusion, ∂h s /∂t is the relative humidity change due to selfdrying, and κ∂T/∂t is the change in relative humidity under the influence of temperature. The following are the expressions and differential equations for the three components of Equation (1).…”

“…It is now understood that once cement concrete pavement has been poured and completed, environmental factors can cause temperature and humidity gradients inside the concrete, resulting in slab surface shrinking, expansion, and warping, which cause large tensile stresses. Ultimately, these stresses can trigger cracking and even spalling [1]. Especially under the coupling effect of high temperature, high humidity, heavy rain, and strong wind, media such as water and erosion ions in the environment accelerate to penetrate into the interior of concrete along microcracks, causing further crack growth, increasing the probability of diseases such as concrete pavement peeling, affecting service life performance, and further reducing service life.…”

Application of Graphene-Based Nanomaterials as a Reinforcement to Concrete Pavements

“…Further, CRCP is expected to last a long while, allowing room for a possible widening due to extra traffic and several overlays due to pavement damage or aging. Moreover, fibers and additions, such as graphene-based nanomaterials, can be also included into CRCP to gain more resistance for common pavement distresses, such as spalling [30] and punchouts, while offering some other greater benefits also, such as insights of reducing slab thickness and amount of rebars. Therefore, it is necessary to investigate how these fibers and additions act in these concrete pavements and improve pavement performance indices.…”

Thermomechanical Analysis of Ceramic Composites Using Object Oriented Finite Element Analysis

“…Recently, OOF2 was used to obtain the stress distribution and Young's modulus in the thermally treated Mg-9 wt.%Li-7 wt.%Al-1 wt.%Sn alloy to enhance the wear resistance [24][25][26]. Further, continuously reinforced concrete pavement α correlation with spalling, performance and mechanical behavior is also studied with OOF2 and results are compared with commercial FE software [27]. Furthermore, the λ and thermal effusivity are simulated for the different regions of TBCs as synthesized by thermal spray processes and suspension plasma spray for gas turbine applications [28].…”