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0-1700-P14 DESIGN STANDARDS FOR CRCP FOR EACH TEXAS ENVIRONMENTAL REGION

0-1700-P14 DESIGN STANDARDS FOR CRCP FOR EACH TEXAS ENVIRONMENTAL REGION. Center for Transportation Research The University of Texas at Austin. Overview. Texas Temperature Data. Collect annual maximum and minimum air temperature data 21 locations Possible data during last 20 years

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0-1700-P14 DESIGN STANDARDS FOR CRCP FOR EACH TEXAS ENVIRONMENTAL REGION

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  1. 0-1700-P14DESIGN STANDARDS FOR CRCP FOR EACH TEXAS ENVIRONMENTAL REGION Center for Transportation ResearchThe University of Texas at Austin

  2. Overview

  3. Texas Temperature Data • Collect annual maximum and minimum air temperature data • 21 locations • Possible data during last 20 years • www.wundground.com • Divide Texas into 4 environmental zones based on average annual temperature range and geographic location

  4. Selected Locations

  5. Maximum Annual Temperature

  6. Minimum Annual Temperature

  7. Average Annual Temperature Range

  8. Texas Environmental Zone

  9. Concrete Temperatures • Concrete Temperatures were calculated for each location and used for input values of CRCP program • PavePro software • Use max. and min. annual temp. for input → conservative results • Maximum and zero stress concrete temperatures • Use default setting for mixture design and temperature distribution • Equation from previous CTR research • Min. concrete temperature = 0.9535AT+6.0749 • AT=minimum ambient temperature (deg.C)

  10. Temperature Differential (DT)

  11. Numerical Simulation using CRCP • Variables for simulation

  12. Numerical Simulation using CRCP • Total 448 sets of data • Use zero-stress temperatures as curing temperatures for simulation • Find corresponding crack width for given conditions • Provide data set for regression analysis

  13. Regression Analysis • Crack width = a X (DT) +b • where • DT = temperature differential • a, b = coefficients • Max. allowable crack width = 0.017 in. • Interpolate CRCP program output to find corresponding steel ratios for maximum allowable crack width for given conditions • Environmental region (Zone) • Thickness • Coefficient of Thermal Expansion (CoTE) of concrete

  14. Sample Regression Results

  15. Design Table for Longitudinal Reinforcement • Design table for longitudinal reinforcement were developed. • Each environmental Zone • Max. allowable crack width = 0.017 in. • Two CoTE of concrete • 4 X 10-6 /°F and 6 X 10-6 /°F • Calculated longitudinal bar spacing based on No. 6 bar • Thickness = 8 – 15 in. (1-in. increment) • Assume double steel mat for 14 and 15-in. thick pavement

  16. Longitudinal Steel Design Table:CoTE = 4 X 10-6 /°F

  17. Longitudinal Steel Design Table:CoTE = 6 X 10-6 /°F

  18. Summary • The annual maximum and minimum air temperature data were collected from 21 locations in Texas. • The State of Texas were divided into 4 environmental zones based on temperature history of selected locations. • Maximum crack width were calculated by numerical simulation using maximum temperature differentials for selected locations. • The corresponding longitudinal steel ratios were calculated by regression analysis. • Design tables for longitudinal reinforcement were provided for each Texas environmental zone.

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