Asphalt Thermometers: All You Need to Know

Asphalt thermometers play a crucial role in ensuring the quality and longevity of pavements, making it essential for industry professionals to understand their unique features, ideal applications, and proper maintenance practices. This comprehensive guide will help you grasp the importance of various types of asphalt thermometers, how to select the ideal one for your needs, and the proper use and maintenance of these essential tools.

Key Takeaways for Asphalt Thermometers

Asphalt thermometers come in various types, each with its own features and benefits.
Selecting the ideal asphalt thermometer requires consideration of temperature range, calibration accuracy, heavy-duty construction and correct measurement techniques.
Popular brands for asphalt thermometers include Deslauriers, Gilson Company & HMA Lab Supply with precision testing & calibration processes for reliability.

Types of Asphalt Thermometers

There are three main types of asphalt thermometers used in the industry: digital infrared thermometers, dial thermometers, and K-type thermocouples. Each type has unique benefits and applications. Understanding these differences can assist you in making a well-informed decision when choosing the best thermometer for your specific needs.

Digital Infrared Thermometers

Digital infrared thermometers are a popular choice for asphalt testing due to their ability to provide precise temperature measurements without contact with the surface. This non-contact method enables quick and efficient measurements, proving its worth as a valuable tool in the field. However, potential drawbacks may include the risk of high-powered infrared waves affecting the eyes, and temporary performance issues due to factors like dust, fog, or frost.

Available models of digital infrared asphalt thermometers include:

MA-774
MA-775
MA-776
MA-778

Each offers unique features to suit various testing needs and at different price points. Infrared thermometers and thermal imaging cameras offer a non-destructive approach to quickly identify deterioration or subsurface flaws, especially beneficial during asphalt placement by recognizing the temperature gradients that aid in determining rolling patterns. With this technology, users can have a clear view of the surface conditions, ensuring optimal results and efficient work.

Dial Thermometers

Dial thermometers are another common choice for asphalt testing due to their ease of reading compared to traditional thermometers. These devices operate by utilizing a metal pointer on a circular scale to indicate temperature measurements, with the temperature sensor expanding with heat, thereby pushing the needle on the dial to indicate the temperature. Dial thermometers are utilized to monitor the temperature of asphalt mixtures during mixing, compaction, and curing processes, ensuring the asphalt is at the correct temperature for maximum performance and quality.

While dial thermometers provide a reliable and accurate method of first measuring asphalt temperature, they might not match the speed and accuracy of digital thermometers. Using the right thermometer for the specific asphalt testing application is vital for a comprehensive insight into the temperature measurements.

K-Type Thermocouples

K-type thermocouples are widely employed in asphalt testing due to their wide operating temperature range, which spans from -200°C to +1350°C, making them suitable for various asphalt testing applications. These thermocouples utilize two different metals to measure temperature, and their advantages include:

Durability and reliability
Accurate temperature measurement
Easy installation and maintenance
Compatibility with standard thermocouple connectors

These features make K-type thermocouples a popular choice for asphalt temperature measurement.

Correct calibration of a K-type thermocouple is vital for ensuring accurate and reliable temperature measurements in asphalt applications. This calibration procedure involves verifying the temperature range of the thermocouple and comparing its readings to a known reference temperature, ensuring accurate and reliable temperature measurements in asphalt applications.

Selecting the Ideal Asphalt Thermometers

The selection of the ideal asphalt thermometer is significant, ensuring precise temperature readings crucial for monitoring temperature during asphalt laying, thereby assuring excellent compaction and high-quality roads. Factors such as temperature range, calibration, and heavy-duty construction play a crucial role in determining the perfect asphalt thermometer for your needs.

Temperature Range

The temperature range is a key factor to consider when selecting an asphalt thermometer to ensure accuracy in temperature readings. Different asphalt mixtures demand specific temperature ranges for optimal compaction and performance, hence the necessity of choosing a thermometer with the appropriate temperature range for successful asphalt paving and maintenance processes.

For example, digital infrared asphalt thermometers typically have a temperature range of -76°F to 1,832°F (-60°C to 1,000°C), while K-Type thermocouples offer a wider temperature range, of -200 to 1260°C (-326 to 2300°F). It is essential to select an asphalt thermometer that has a temperature range suitable for the intended application to guarantee accurate temperature measurements.

Calibration and Accuracy

In asphalt thermometers, calibration and accuracy are of utmost importance to ensure the thermometer provides accurate temperature readings. Routine calibration helps sustain the accuracy of the thermometer and verifies that it abides by industry standards and regulations. Accurate temperature measurements are essential in asphalt applications to guarantee the quality and safety of the asphalt mixture.

An asphalt thermometer is calibrated for accuracy by manually calibrating it with a large glass container containing crushed ice and cold tap water. The thermometer stem or probe is then inserted into the container to guarantee accurate readings. It is essential to adhere to the specific requirements of the test method being used, as some test methods may necessitate shorter intervals.

Heavy-Duty Construction

Heavy-duty construction for asphalt thermometers is advantageous because asphalt is a resilient material designed to withstand vehicular and foot traffic, corrosion, and extreme weather. Therefore, the thermometer used to measure the temperature of the asphalt needs to be able to endure these type of harsh conditions and provide accurate readings.

Utilizing a heavy-duty construction ensures that the thermometer is robust and can withstand the demands of the asphalt paving process. Heavy-duty asphalt thermometers are typically manufactured utilizing materials such as stainless steel for the stem and probe of thermometers, as well as resilient thermocouples for temperature measurement.

Proper Use and Maintenance of Asphalt Thermometers

To achieve accurate and consistent results, following appropriate measurement techniques, cleaning and storage practices, and calibration procedures is vital when using asphalt thermometers. Proper use and maintenance will not only guarantee precise temperature readings but also prolong the lifespan of your asphalt thermometer.

Correct Measurement Techniques

When using a digital infrared thermometer to measure asphalt temperature, follow these steps:

Set the thermometer to the correct temperature range for asphalt measurements.
Stand an appropriate distance from the asphalt surface.
Aim the thermometer at the asphalt surface.
Press the measurement button.
Repeat the measurement at different locations on the asphalt surface to ensure accurate readings.

To start, simply insert the stem of the dial thermometers into the asphalt mix and allow the temperature to stabilize for approximately one minute before taking the reading on the page.

In the case of K-type thermocouples, follow these steps:

Select an appropriate thermocouple probe.
Connect the probe to a compatible thermometer.
Immerse the probe into the asphalt.
Wait for the temperature to stabilize.
Observe the temperature on the thermometer.

Cleaning and Storage

Proper cleaning and storage of asphalt thermometers are essential to maintain their accuracy and longevity. To clean an asphalt thermometer, use a cotton ball or pad soaked in at least 60 percent rubbing alcohol and gently clean the thermometer’s sensor, taking care to avoid harsh chemicals or abrasive cleaners that may damage the digital asphalt thermometer itself.

For storage, follow these guidelines:

Keep the thermometer in a clean and dry place
Preferably store it in a protective case or wrap it in a soft cloth to prevent damage or contamination
Avoid exposing the thermometer to extreme temperatures or direct sunlight during storage, as this can negatively affect its accuracy and longevity.

Calibration and Recalibration

Regular calibration and recalibration are vital for asphalt thermometers to ensure accurate measurements. Asphalt thermometers should be calibrated at least every 3 years, or as specified by the test method or specification, to guarantee precise readings.

If an asphalt thermometer requires recalibration, follow these steps:

Contact an agency accredited for ISO/IEC 17025 for thermometer calibration.
Send the thermometer to them for recalibration.
Once the recalibration is completed, obtain a calibration certificate to ensure the thermometer’s continued accuracy and reliability.

Summary

In conclusion, understanding the different types of asphalt thermometers, their applications, and proper maintenance practices is essential for industry professionals. By selecting the ideal asphalt thermometer for your specific needs, using correct measurement techniques, and following proper cleaning, storage, and calibration practices, you can ensure accurate and consistent results in your asphalt testing endeavors. Remember to explore the offerings of top asphalt thermometer brands and choose the one that best suits your requirements.

Frequently Asked Questions

How do you check the temperature of asphalt?

To check the temperature of asphalt, it is best to use a handheld non-contact infrared thermometer held 3 feet above the mat or by inserting a calibrated dial thermometer into the mat and taking at least five readings.

What is the temperature of a digital thermometer for asphalt?

The Pocket Dial Thermometer offers a full dial and temperature range of 50 to 500F, while the digital K-type thermometer has an operating range of up to 1292 degrees F. Lastly, the hand-held digital thermometer operates with a 9V battery and has a switchable resolution between -99 to +1372 °C.

Which infrared thermometer is the most accurate?

The Fluke 62 Max is the most accurate infrared thermometer, with a measurement range between -22 degrees and 1,202 degrees Fahrenheit and an accuracy rating of 1 percent.

What are the main types of asphalt thermometers?

The main types of asphalt thermometers are digital infrared thermometers, dial thermometers and K-type thermocouples, allowing for accurate readings to be taken quickly and efficiently.