Concrete Coefficient of Thermal Expansion (CTE) System

Concrete Coefficient of Thermal Expansion (CTE) System

Understanding the Coefficient of Thermal Expansion (CTE) is crucial for designing durable concrete pavements. This advanced CTE System accurately predicts how concrete expands and contracts with temperature changes, directly impacting pavement longevity. The NCHRP 1-37A research program highlighted the critical role of these thermal movements in pavement performance, leading to the integration of CTE values into the Mechanistic-Empirical Pavement Design Guide (MEPDG). Our system fully complies with AASHTO T 336, the standard test method for CTE determination, and is designed to support agencies in evaluating and developing optimal concrete mixes.

Automated Precision for Reliable Results

The system streamlines the testing process for maximum efficiency and accuracy. Once a saturated 4x7in (101.6x177.8mm) concrete specimen is mounted in the measuring frame and submerged in the water bath, testing begins with a simple press of a button. The system precisely records length changes at controlled temperatures, ranging from 10°–50°C (50°–122°F). Upon completion, the CTE value is automatically computed and reported, eliminating manual errors and ensuring consistent results.

Key Features and Components:

This CTE System represents a significant leap forward in accuracy, repeatability, and versatility compared to existing systems.

• Pre-loaded Software: A dedicated laptop computer, included with the system, automates the entire process—measuring, recording, and calculating final CTE values in strict accordance with AASHTO T 336. This intuitive software simplifies complex calculations and data management.
• Dual-Sample Water Bath: The portable, benchtop stainless steel water bath offers a generous 10-gallon (38L) capacity and the unique ability to test two samples simultaneously. This dual-testing capability, achievable with an additional HMA-114C CTE Measuring Frame and HMA-113 LVDT Calibrator (sold separately), significantly enhances sample throughput and efficiency in your lab.
• High-Precision Temperature Control: A state-of-the-art water circulation unit, equipped with a thermistor offering 0.01°C resolution and ±0.05°C accuracy, meticulously controls and records bath temperatures. Water is recirculated every twenty seconds, guaranteeing uniform temperature distribution around the specimens.
• Consistent Water Level: A sophisticated water level control device eliminates the effects of evaporative loss, maintaining a precise and constant water level throughout the entire test duration, which is critical for accurate thermal measurements.
• Robust Measuring Frame: The heavy-duty, adjustable specimen measuring frame accommodates sample heights from 4 to 8.5in (102 to 216mm). Constructed from Type 304 stainless steel, it ensures uniform expansion characteristics, minimizing measurement variability due to the frame itself.
• Ultra-Sensitive LVDT: A highly precise Linear Variable Differential Transformer (LVDT) is securely mounted to the measuring frame. With a travel range of 1.27mm and an astounding resolution of 3.1x10-8mm, this LVDT guarantees extremely accurate and reliable length change measurements, capturing even the most minute thermal expansions or contractions.

Comprehensive System Package:

The CTE System is a complete solution, ready for immediate use, and includes:

• Laptop computer preloaded with CTE software and necessary interfaces.
• Benchtop stainless steel water bath, 10gal (38L) capacity, 25x16x13in (635x406x330mm) WxDxH.
• One stainless steel measuring frame with integrated LVDT.
• Stand-alone water circulating unit with thermistor temperature probe.
• Water level control device.

The system is UL Certified and operates efficiently at either 115V, 60Hz or 240V, 50Hz, providing flexibility for various laboratory setups.

Calibration and Verification:

For complete confidence in your results, Calibration and Verification Specimens are available for separate purchase. The Calibration Specimen is made from 304 Stainless Steel, and the Verification Specimen from 410 Stainless Steel. For enhanced traceability and assurance, Grade 5 Titanium Steel and Nickel Calibration Specimens can also be certified to ASTM E228 by an ISO 9001 facility.

Expand Your Testing Capacity:

An additional CTE Measuring Frame and LVDT Calibrator, sold separately, significantly boosts your lab's throughput by allowing simultaneous testing of two specimens. These frames are designed for direct connection of the LVDT to your computer's USB port. The LVDT Calibrator with Digital Micrometer can be acquired separately to periodically verify the precise performance of the LVDT.

Features Summary:

• Predicts thermal expansion and contraction in concrete pavement, enhancing mix design.
• Precisely measures length changes of laboratory specimens with high resolution.
• CTE-software driven process fully complies with AASHTO T 336.
• Adjustable measuring frame constructed from Type 304 stainless steel, featuring an integrated LVDT.
• Optional Verification Specimen certification to ASTM E228 by an ISO 9001 facility.
• Dual-sample testing capability with additional components for increased efficiency.
• Automated data acquisition and calculation, reducing manual error.
• High-precision temperature control and uniform water circulation.
• Elimination of evaporative loss for consistent testing conditions.

Included Items:

• Coefficient of Thermal Expansion (CTE) Concrete System:
  • Specimen Measuring Frame with LVDT
  • Insulated Stainless Steel Water Bath (approx. 10gal / 38L capacity)
  • Water Circulating Unit w/ temperature probe
  • Water Level Control Device
  • Laptop Computer w/ CTE software and interfaces

Specifications:

• Water Bath Capacity: 10gal (38L)
• Material Specimen Measuring Frame: Type 304 Stainless Steel
• Electrical: 115V, 60Hz or 240V, 50Hz
• Dimensions, Heater/Cooler: 15 x 27 x 23in (381 x 685.8 x 584.2mm) WxDxH
• Water Bath Dimensions: 25 x 16 x 13in (635 x 406.4 x 330.2mm) WxDxH
• Estimated Weight: 170.0lb (77.11kg)
• Meets Standard(s): AASHTO T 336