ASTM C780-20 PDF Download

ASTM C780-20 is a standard test method that outlines procedures for the preconstruction and construction evaluation of mortars used in plain and reinforced unit masonry. The purpose of this standard is to establish specific and overall performance characteristics for mortar systems.

The preconstruction evaluation involves testing mortars that are prebatched by weight to determine their suitability for the intended masonry construction. The recommended tests include consistency determinations, consistency retention, mortar water content, mortar aggregate ratio, mortar air content, and compressive strength testing. These tests help in gauging the water additions, setting characteristics, water content, aggregate-to-cementitious materials ratio, air content, and strength of the mortars.

The construction evaluation, on the other hand, involves repetitive testing during the actual construction process to measure batch-to-batch variations in mortar production. The tests conducted during construction may include consistency, consistency retention, mortar water content, mortar aggregate ratio, mortar air content, and compressive strength testing. These tests help in assessing variations in mix ingredients, mixing time, mix proportions, and environmental conditions.

It's worth noting that the test results obtained using this standard are not required to meet the minimum compressive values specified in other standards. The standard also provides additional guidance and explanatory notes to aid in the understanding and implementation of the test methods.