A Discussion of the Benefits and Problems of ASTM C 1324 for Analyzing Hardened Masonry Mortars

Abstract

Abstract Laboratory testing of mortars by chemical analysis and petrography is generally appropriate to determine mortar composition, and to provide a basis for the formulation of compatible repair or replacement mortars. In cases of masonry distress and failures, analysis by C 1324 alone is often less useful unless the laboratory work is guided by knowledge obtained in the field. In addition to requiring the technical skills of experienced chemists and petrographers, the application of C 1324 requires knowledge of the specifications for mortar for unit masonry and benefits from the knowledge of how mortars are prepared and installed. The quality of the sampling for laboratory tests, the physical condition of the samples obtained, and the mortar constituents can all influence the reliability of the results obtained by the chemical analysis and the petrographic examination. We review the development of the standard, discuss related standards, and present our experience with modern mortars prepared in the field and tested in the laboratory in accordance with ASTM C 1324 to provide insight into the results and limitations of such analysis.