High Performance Concrete Pavements
CHAPTER 9. INDIANA 1 (I-65 at SR-60, Clark County)
Indiana is interested in building a jointed concrete pavement with an extended performance life. Research has suggested that jointed concrete pavements built with "low slab curvature" also have extended pavement life. This project, located on I-65 in Clark County (see Figure 30), includes various construction and materials properties that will be evaluated to assess concrete slab response to environment and the resulting stress/strain relationships.
Figure 30. Location of IN 1 project.
This project will investigate the relationship between specific construction and materials factors and long-term pavement performance by use of an instrumented pavement. These experimental sections will have 38 state-of-the-art vibrating wire strain gauges to monitor the strain in the pavement slabs, 5 tilt meters to monitor the curling direction and tendency, and 4 time domain reflectometers to determine the moisture content in the pavement base and subgrade. A total of 186 data acquisition channels and an automated data acquisition unit will be employed to monitor the behavior of the pavement slabs. In addition, there will be 75 iButton™ temperature sensors (sensors in the form of a button that has a processor and battery life of 3 years to process data inside the button) that will monitor the pavement temperature profile inch-by-inch, to determine the onset of temperature curling in concrete pavement. A GroundHog traffic monitoring system will be also in place to monitor the traffic and vehicle classifications.
A weather station to monitor air temperature, relative humidity, wind speed, wind direction, precipitation, rate of sub-surface temperature and solar radiation will provide data to predict the behavior of the pavement slabs, especially the correlation between climatic conditions and the pavement behavior response.
The results of this experimental project, when fully implemented, will minimize or eliminate the needs of early pavement rehabilitation and frequent pavement maintenance.
Project Design and Layout
Three one-directional lanes featuring a 355.6-mm (14-in.) thick slab will be constructed over a 2.49-km (1.55-mi) segment of I-65 during the 2004 construction season. Data analysis from this project will be directed toward evaluating the following:
- Low built-in curl (controlling temperature gradients during construction).
- Low sensitivity to moisture warping (low permeability).
- Low sensitivity to temperature gradients after construction (low thermal coefficients of concrete).
- Fracture properties, tensile strength, elastic modulus, entrained air, permeability, and thermal expansion from field concrete.
- Materials properties that impact the above properties include low w/c, aggregate soundness, and coarse aggregate fracture properties.
The estimated time of completion for this project is 36 months. The first 12 months will concentrate on a state-of-the-practice review of modern instrumentation to measure important parameters that influence the performance of concrete pavement.
Static and dynamic sensors will be embedded in the pavement structure at specific locations to measure the appropriate parameters. The dynamic sensors are used to measure pavement response to traffic while the static sensors are used to measure the pavement response to changes of environmental conditions such as variations of temperature, moisture, and curling during construction, after construction, and in-service pavement. In addition, the traffic and weather conditions will be monitored by using a GroundHog and an RTWin weather station, respectively. Table 13 summarizes the instrumentation currently being considered for installation for this project (Nantung 2004).
The second 12-month period will consist of the data analysis described. This period will include laboratory testing in conjunction with the joint project with Purdue University to complete a finite element analysis, damage model, slab contact model, layered base model, and thermal gradient model. Data analysis from this project will be analyzed using the new finite element models to determine the damage analysis of two different dimensions of PCC slabs.
The final 12 months will include additional analysis and verification of all data analysis to be included in a final report.
State Monitoring Activities
Field monitoring will be limited to the first 12 months after construction.
Selection of the state-of-the-art monitoring equipment has been completed. Currently Indiana DOT is performing laboratory checks on all equipment prior to implementation during construction. A summary of the proposed instrumentation for this project is shown in Table 13 (Nantung 2004).
Table 13. Summary of Proposed Instrumentation (Nantung 2004)
|SENSOR TYPE||MEASUREMENT TYPE||PURPOSE|
|Vibrating Wire Tiltmeter||Tilt angle||Measure the curling at all four corners of the slab.|
|Time Domain Reflectometer||Moisture||Measure the moisture content of the soil under the slab.|
|IButton™||Temperature||Measure the temperature profile in the pavement.|
|GroundHog™||Traffic||Measure vehicle volume, vehicle speed and length, road surface temperature, roadway wet/dry condition, and amount of salt used for anti-icing.|
|RTWin™ Weather Station||Weather||Measure air temperature, relative humidity, wind speed, wind direction, and precipitation.|
Points of Contact
575 N Pennsylvania St., Room 254
Indianapolis, IN 46204
Tommy E. Nantung
(765) 463-1521 x248
(765) 463-1521 x 244
INDOT Research Division
P.O. Box 2279
West Lafayette, IN 47906
Nantung, T. E. 2004. High Performance Concrete Pavement. Indiana Public Works News , Volume 5, Number 1. Anchor Media Co.