This work item proposes to remove the requirement for the ASTM C151/C151M autoclave expansion test.
1 ASTM Committee C01 has approved removing the autoclave expansion test (ASTM C151/C151M) requirements from ASTM C150/C150M with no replacement; this change was published in the revision of that specification in 2022. Committee C01 is also re-evaluating the use of C151/C151M in other C01 standards with the goal of eliminating or minimizing the use of C151/C151M. Ballot items have been approved by C01.10 and C01.20 to remove C151/C151M from Specifications C595/C595M, C226, and C465.
2 The usefulness of the autoclave expansion test to identify the potential for deleterious expansion in concrete or masonry mortars due to unsound cementitious materials has been controversial. With respect to portland cements used in concrete, there has not been a demonstrated correlation between autoclave expansion test specification limits and soundness of concrete (Mehta 1978). No concrete failures have been attributed to cements failing soundness tests or containing high MgO contents in the last 60 years, nor have cases of MgO-related soundness failures in countries where the test is not required (Klemm 2005). Similarly, concerns regarding the application of the autoclave expansion test to hydrated lime used to produce masonry mortars have been documented (Lovewell 1975). Hydrated limes that would fail C151 autoclave expansion tests requirements for cements, have a record of providing sound, durable masonry mortars (Davison 1975).
3. Regarding natural cements, there have been no known failures of natural cements to meet the requirements of C151/C151M for cements produced since the 2006 reinstatement of C10/C10M. There have also been no known mortar or concrete failures attributed to natural cement unsoundness related to MgO.