Early Opening of Concrete Pavements to Traffic - Lev Khazanovich et al

Early Opening of Concrete Pavements to Traffic

Lev Khazanovich, Lucio Salles, Katelyn Kosar, Haoran Li IRISE ANNUAL MEETING MAY 24, 2021 1 University of Pittsburgh | Swanson School of Engineering

The Research Problem The current empirical methods for determining traffic-opening criteria are overly conservative.

An innovative mechanistic-based procedure for quantifying the risk of premature failure and long-term damage caused by traffic opening will facilitate reduction of unnecessary construction delays, construction and user costs.

University of Pittsburgh | Swanson School of Engineering

Project Approach

Task A: Literature review Task B: Laboratory and field testing Task C: Develop mechanistic-empirical model Task D: Conduct traffic simulation Task E: Final Report

University of Pittsburgh | Swanson School of Engineering

ACPA Guidelines (1994)

University of Pittsburgh | Swanson School of Engineering

Laboratory and Field Testing Two concrete mixtures: 1. Long-Life Conventional 2. High Early Strength (7 hours) Three tests: 1. Laboratory: Compressive and flexural strength 2. Maturity: Lab and Field 3. Ultrasound: Lab and Field University of Pittsburgh | Swanson School of Engineering

Laboratory Testing High Early Strength (HES) mix compressive strength development 4000

4000

Maturity

3000 2500

7h

2000

y = 1666.87ln(x) - 7544.51 R² = 0.96

1500 1000

3500

1 day

5h

Compressive Strength (psi)

Compressive Strength (psi)

3500

3000

2000 1500 5h 1000

3h

0 0

200

400

600

L abor ator y M atur ity (℃-hr s )

800

1000

7h

2500

500

500

1 day

Shear Wave Velocity

0 1000

y = 6.2377e0.002751x R² = 1.00

3h 1200

1400

1600

1800

2000

Slab Shear Wave Velocity (m/s)

University of Pittsburgh | Swanson School of Engineering

2200

2400

Laboratory Testing Long-Life Conventional Mix Compressive Strength Development 6000

6000

Compressive Strength (psi)

7 days

5000 3 days

4500

5 days

y = 855.83ln(x) - 2,360.74 R² = 0.94

4000 3500

14 days

Compressive Strength (psi)

Maturity

5500

5500

14 days

5 days

4500

3 days 4000 y = 11.29x - 26,286.23 R² = 0.99

3500 1 day

3000 1800

7 days

5000

1 day

800

Shear Wave Velocity

2800

3800

4800

5800

6800

Cyllinder M atur ity (℃-hr s )

7800

8800

9800

3000 2600

2650

2700

2750

Beam Shear wave velocity (m/s)

University of Pittsburgh | Swanson School of Engineering

2800

2850

Field Testing Variability of concrete properties 2500 Construction day: 3 to 24 hours after pavement construction

24 h

1 day

9h

1500

TE

Subsequent days

CLN

Thermocouples

CLN

1700

CLS

1900

TC

CRN

5h

CRS

2100

C1.1

CRN

TC

CLS

TE

CRS

1300 3.5h

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

University of Pittsburgh | Swanson School of Engineering

C1.3

Measurement Cycles

a.m.

900

S1 HES2 HES3

1100

.2

Shear Wave Velocity (m/s)

2300

14 days

Mechanistic-Empirical Model

The research team was directed by the Technical Panel to develop a comprehensive procedure rather than a simple equation.

The proposed model: Uses ultrasound-based strength development assessment Assesses a probability of failure due to early opening Will be implemented into a web-based tool

University of Pittsburgh | Swanson School of Engineering

Project Status Tasks 1 and 2 have been completed Task 3 ME procedure and web-based tool development – a significant progress was made The model has been developed: A discrepancy between lab- and field- measured shear wave velocity was identified A maturity-based correction was developed A re-evaluation of the velocity calculation is underway

An alpha–version of the tool has been developed and currently is under debugging

A 3-month time-extension will be requested University of Pittsburgh | Swanson School of Engineering

Task C: Develop Mechanistic-Empirical Model

The tool needs to be finalized University of Pittsburgh | Swanson School of Engineering

Discrepancy Between Lab and Field Velocities

Compressive Strength (psi)

6000

5000

4000

3000

2000

Maturity

SWV

Adjusted SWV

1000

0 0

2

4

6

8

10

Concrete Age (days)

12

14

16

University of Pittsburgh | Swanson School of Engineering

Application of Research Results

Relatively early concrete strength can be achieved with conventional concrete mixes PennDOT (Neal Fannin) and FHWA Concrete Mobil Lab will further investigate the use of the ultrasound dry point contact technology for the strength development assessment A web-based tool for the early opening analysis will be available soon

University of Pittsburgh | Swanson School of Engineering