ASTM C 1072 : 2019

1.1.1The first method is the “Test Method for Laboratory-Prepared Specimens.” Its purpose is to compare the bond strengths (under the given conditions) of masonry mortars. It could be used, for example, to check the quality of mortar products after production, or to indicate the bond strength (under the given conditions) of a mortar product without requiring the product to be tested in combination with many different units. It is not intended to represent field conditions. It uses standard concrete masonry units. Mortars are batched by weight equivalents of volume proportions and are mixed to a prescribed flow. Prisms are constructed using a jig and are bag-cured.

1.1.2The second method is the “Test Method for Field-Prepared Specimens.” Its purpose is to evaluate the bond strength (under the given conditions) of a particular unit-mortar combination, either for preconstruction evaluation of materials or for quality control purposes during construction. Mortars are batched conventionally, and the flow is not prescribed. Prisms are constructed conventionally (no jig) and are bag-cured.

1.1.3The third method is the “Test Method for Prisms Removed from Existing Masonry.” Its purpose is to evaluate the bond strength of unit-mortar combinations of prisms cut from existing walls.

1.1.4The three methods are not consistent, nor are they intended to be. They are intended to be used for three different purposes. To make this clear, the three methods are presented separately.

1.1.5Appendix X1 suggests two possible criteria for assessing the bond strength values obtained using these test methods. These possible evaluation criteria are given for illustration only and are not mandatory.