ISO/IEC 17025 Accredited Calibration for AASHTO-Accredited Labs 

AASHTO accreditation demands precision, and your calibration provider has to meet that standard too. Accredited Labs is the largest CMT calibration services provider in the United States, with 40+ locations nationwide and ISO/IEC 17025 accreditation across the full range of construction materials testing disciplines. We know the equipment you use, the standards you're held to, and what it takes to keep your lab compliant and audit-ready. 

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Calibration Services for AASHTO-Accredited Labs 

Maintaining AASHTO accreditation means your testing equipment has to perform every time, on every project. From concrete and asphalt to soils and aggregates, the instruments your lab depends on must be calibrated to traceable standards, documented to satisfy assessors, and serviced by technicians who understand the demands of accredited CMT work. 

When testing equipment drifts out of calibration, the consequences extend beyond a failed assessment. Structural failures, project delays, regulatory violations, and safety hazards are all on the line. The Accredited Labs network provides comprehensive CMT equipment calibration services built specifically for the accuracy and compliance requirements of AASHTO-accredited laboratories.

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Our Process 

Construction materials testing equipment calibration involves verifying and adjusting instruments that evaluate concrete, asphalt, soil, aggregate, and other materials used in construction projects. Each instrument is compared to certified reference standards, including proving rings, load cells, and dimensional gauges, to identify any deviations from AASHTO and ASTM specifications.

During calibration, technicians evaluate the instrument across its full testing range, assess system performance, verify dimensional accuracy, and document all variations. If an instrument cannot be brought back into specification, you receive detailed reporting with the data needed for corrective action or replacement planning.

Every calibration follows AASHTO testing specifications and ASTM International standards, ensuring consistency, reliability, and full measurement traceability. Each instrument is returned with documentation linking its accuracy to national measurement standards, supporting your accreditation requirements and quality system obligations.

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Types of Construction Materials Testing Equipment We Calibrate

Our comprehensive construction materials testing equipment calibration services cover the complete spectrum of instruments used for construction materials evaluation:

  • Concrete Compression Testing Machines: Hydraulic and digital compression testers that determine concrete compressive strength through cylinder and cube testing. These critical instruments require calibration using certified proving rings or load cells to ensure accurate strength determination for structural concrete acceptance and quality control.

  • Concrete Flexure and Tensile Testing Equipment: Testing machines that measure concrete flexural strength, splitting tensile strength, and modulus of rupture for pavement design and structural applications. Calibration ensures accurate strength characterization for engineering design and quality verification.

  • Asphalt Marshall Stability Apparatus: Complete systems including loading frames, flow meters, and water baths used for asphalt mix design and quality control testing. Calibration verifies load measurement accuracy, deformation measurement, and temperature control that determine asphalt mixture performance characteristics.

  • Nuclear Density Gauges: Portable instruments using radioactive sources to measure soil and asphalt density and moisture content in field applications. These regulated devices require specialized calibration procedures, radiation safety compliance, and documentation for regulatory agencies and transportation departments.

  • Sand Cone and Rubber Balloon Density Equipment: Field density testing apparatus used for soil compaction verification requiring calibration of volume measurements, sand densities, and calculation procedures that determine in-place soil density for earthwork quality control.

  • Proctor Compaction Equipment: Laboratory compaction apparatus including compaction hammers, molds, and accessories used to determine optimum moisture content and maximum dry density for soil compaction specifications. Calibration ensures proper compactive effort and accurate density determination.

  • Concrete Air Content Meters: Pressure-type and volumetric air meters that measure entrained air content in fresh concrete for freeze-thaw durability and workability control. Calibration verifies pressure accuracy and volumetric measurements critical for durable concrete production.

  • Concrete Slump and Flow Testing Equipment: Slump cones, flow tables, and workability testing apparatus used to evaluate fresh concrete consistency and placement characteristics. Calibration ensures proper dimensions and measurements for workability specification compliance.

  • Sieve Analysis Equipment: Complete sieve sets, sieve shakers, and gradation analysis equipment used for aggregate quality control and mix design proportioning. Calibration verifies sieve opening dimensions and shaker performance for accurate particle size distribution determination.

  • Aggregate Testing Equipment: Instruments for aggregate specific gravity, absorption, soundness, and deleterious substances testing that characterize aggregate quality and performance. Calibration ensures accurate property determination for mix design and quality specifications.

  • Soil Classification and Atterberg Limits Equipment: Testing apparatus for liquid limit, plastic limit, and plasticity index determination used for soil classification and engineering property correlation. Calibration verifies equipment dimensions and performance for accurate soil classification.

  • Pavement Coring Equipment and Core Analysis Tools: Diamond coring machines and core dimension measurement tools used for in-place pavement evaluation. Calibration ensures accurate core recovery and dimensional measurements for pavement assessment and quality verification.

  • Moisture and Humidity Testing Equipment: Ovens, moisture analyzers, and humidity chambers used for moisture content determination in concrete, soil, and aggregates. Calibration ensures accurate temperature control and moisture measurement for proper material characterization.

  • Temperature Measurement and Control Equipment: Thermometers, temperature probes, and environmental chambers used throughout materials testing for temperature-sensitive tests and curing control. Calibration ensures accurate temperature measurement and control for valid test results.

FREE DOWNLOAD  

CMT Equipment Calibration & Audit Readiness Checklist


Our free download gives you a practical, equipment-specific checklist covering concrete, asphalt, aggregate, and soil testing instruments — with calibration criteria, interval guidance, and the items most commonly cited in ISO/IEC 17025 and AASHTO assessments.


Download it now and be ready for every audit.