Programs that work for you

"They are rigorous, they’re about making sure our labs, personnel, and test methods conform, that they’re in compliance. They’re independent, not driven by a vendor or a construction company.”

California Department of Transportation

Philip Stolarski, Former Deputy Division Chief, DES-METS & GS

55+	years of experience
3,000+ PSP participants
23,000+ samples shipped per year
1,000 laboratory assessments per year
2,000+ accredited labs

News

AASHTO Accreditation Policy on Aggregate Correction Factors as described in AASHTO T 152 and ASTM C231

Dec 03, 2025

The AASHTO Accreditation Program has released a new policy and guidance document. "AASHTO T152 and ASTM C231: Aggregate Correction Factors for Concrete Air Content Determinations Using Pressure Meters" clarifies how laboratories should determine and apply the aggregate correction factor required by AASHTO T 152 and ASTM C231. It outlines AASHTO Accreditation Program expectations for compliant practice and resolving related nonconformities. Until updates are made within ASTM C231, this document serves as the essential reference for accredited laboratories.