ACI PRC-214.4-21 (IN-LB, SI) PDF Download

The ACI PRC-214.4-21 standard provides guidance on the process of obtaining core specimens from concrete structures and interpreting the results of compressive strength tests conducted on these cores. The standard emphasizes that core testing is a direct method for determining concrete compressive strength and can be used to assess compliance with strength-based acceptance criteria in new structures or to evaluate the structural capacity of existing structures. However, the interpretation of core strength test results can be complicated by various factors that affect in-place concrete strength and the inherent scatter in the test data.

The standard reviews factors that can affect in-place concrete strength to help in selecting appropriate sampling locations that align with the objectives of the investigation. It also presents strength correction factors that can be used to convert the measured strength of nonstandard core-test specimens to the strength of equivalent specimens with standard dimensions and moisture conditioning. These correction factors have been derived based on data for normal weight concrete with strengths ranging from 2000 to 13,400 psi (14 to 92 MPa).

Furthermore, the standard provides guidance on checking the strength compliance of concrete in structures under construction and methods for determining equivalent specified strength to assess the capacity of existing structures.