Concrete Testing Thermometer Procedures and Training
Using a Concrete Testing Thermometer
When pouring concrete for construction projects, it is important to test the temperature of the fresh concrete mix. An ASTM C1064 concrete testing thermometer is used to measure the temperature and ensure it meets specifications. Proper concrete curing temperature leads to higher strength and durability.
Inserting the Concrete Testing Thermometer
Per ASTM C1064 standards, insert the concrete testing thermometer at least 3 inches into the fresh concrete after it has been placed and consolidated. Slowly insert the thermometer to avoid making large voids in the concrete. The tip should be surrounded by concrete to get an accurate reading.
Use a tamping rod to close any small voids around the concrete testing thermometer after inserting it. Tamp the concrete firmly around the sides of the thermometer to ensure good contact between the instrument and concrete. This allows the thermometer sensor to equilibrate with the concrete temperature.
Testing Duration
The standards state that the thermometer for testing concrete must be left in place for a minimum of 2 minutes before reading the temperature. Maximum duration is 5 minutes. This gives time for the sensor in the instrument to reach the true temperature of the concrete for an accurate reading.
During the test, the concrete may heat up due to the heat of hydration as cement and water react. A longer testing time allows this chemical reaction's heat to transfer to the sensor. Testing for the full 5 minutes produces the most accurate results.
Proper Use of Concrete Testing Thermometers
Following the right procedures when using concrete testing thermometers is critical for proper quality control and workmanship.
Preparation
Before placing concrete, the thermometer for concrete testing needs to be calibrated if required by the manufacturer's instructions. This ensures accuracy in the field. The display should be set to show either degrees Fahrenheit or Celsius as needed.
Protection of the instrument from damage is important as well. The sensor probe is delicate and can break if abused. Transport the thermometer carefully to the job site and avoid dropping or striking it accidentally while working.
Reading Temperatures
Once the minimum test duration has passed, read the temperature display on the dial or digital readout. Record the result to the nearest 1 degree. Remove the concrete test thermometer promptly once finished to avoid leaving a hole in the slab.
Compare the reading to the acceptable range for the concrete mix design. Typical limits are 50-90°F. If outside this range, adjustments to materials or procedures may be needed before additional concrete placement.
Documentation
It is critical to properly document all concrete temperature test results as part of the quality process. Record the time, exact test location, thermometer ID, and temperature reading to provide proof of compliance.
Provide the test data to the project manager or quality manager for evaluation. Failed tests or unusual results need to be noted for further investigation or remediation.
Concrete Thermometer Types
Several styles of thermometers for testing concrete are available to suit different needs and budgets:
Dial Thermometers
The most affordable option is a dial thermometer for concrete. It contains a bimetallic coil sensor that moves a needle on a round dial display. Resolution is generally 1 degree. Dial thermometers for concrete testing range from $10-50 USD.
Digital Thermometers
Digital concrete thermometers show the temperature on an LCD or LED numerical display. They contain either a thermistor or thermocouple sensor. Accuracy is ±1-2°F. Prices range from $30-300 depending on features.
Data Logging Models
Advanced concrete data loggers have the same sensors but can record up to 2,000 temperature measurements with timestamps for downloading. Analysis software is included. Data loggers sell for $150 and up.
Certifications for Concrete Testing
Proper training and certification are essential when testing concrete in the field. Some of the common certification programs are:
ACI Concrete Field Testing Technician - Grade I
The American Concrete Institute (ACI) Concrete Field Testing Technician Grade I certification is an entry-level program focused on test methods and documentation for fresh concrete. The exam covers slump, temperature, air content, unit weight and sampling.
NICET Concrete Technician Certifications
The National Institute for Certification in Engineering Technologies (NICET) offers testing technician certifications at multiple levels. NICET exams cover concrete properties, mix designs, quality control concepts, and test procedures.
ICC Concrete Field Testing Technician
The International Code Council (ICC) concrete field technician program teaches requirements from IBC, ACI, and ASTM standards. The exam includes concrete sampling, slump, temperature, air content, unit weight and yield testing.