Masonry Magazine February 1994 Page. 42
Table 1. ASTM C780 Mortar Test Procedures
| Annex | Test Procedure | Significance | Related Variables |
|---|---|---|---|
| A1 | Consistency by Cone Penetration Test Method | Similar to laboratory measured flow. Can be used in conjunction with water content determinations and compressive strength tests to provide additional information on relationships between these variables. | Water content, mixing time, air content, sand gradation, sand particle shape, and aggregate ratio. |
| A2 | Consistency Retention of Mortars for Unit Masonry | Used to establish setting and stiffening characteristics of plastic mortar. | Mixing time, air content, sand gradation, sand particle shape, aggregate ratio, and stiffening characteristics of cementitious materials. |
| A3 | Initial Consistency and Consistency Retention or Board Life of Masonry Mortars Using a Modified Concrete Penetrometer | Purpose is similar to Annex A1 and A2 except that method focuses on job site measurement of these properties. Results are perhaps more reflective of board life characteristics of mortar as experienced by mason. | Water content, mixing time, air content, sand gradation, sand particle shape, aggregate ratio, and stiffening characteristics of cementitious materials. |
| A4 | Mortar Aggregate Ratio Test Method | Determines ratio of aggregate to cementitious materials in a plastic mortar sample. Can be used as a quality control test of batching procedures. | Water content, sand gradation, bulking of sand, batching. |
| A5 | Mortar Water Content Test Method | Used in calculation of aggregate ratio test results. | |
| A6 | Mortar Air Content Test Method | Can be used as a quality control test of air content of job mixed mortar. | Mixing time, temperature, sand properties, and properties of cementitious materials. |
| A7 | Compressive Strength of Molded Masonry Mortar Cylinders and Cubes | Provides information on the strength development characteristics of the mortar. When used in conjunction with preconstruction evaluation tests, results can be used to evaluate uniformity of mortar production during construction. | Elapsed time between mixing, sampling, and molding; consistency when molded, air content, water content, aggregate ratio, mixing time, sand properties, and properties of cementitious materials. |
| A8 | Splitting Tensile Strength of Molded Masonry Mortar Cylinders | Provides information on the tensile strength development characteristics of the mortar. | Elapsed time between mixing, sampling, and molding; consistency when molded, air content, water content, aggregate ratio, mixing time, sand properties, and properties of cementitious materials. |
Cube molds, when used, meet the requirements of ASTM C109 particularly the dimensional tolerance limits.
Cylinder molds, when used, comply with requirements of ASTM C470. (Note that cylinder specimens yield lower results than cubes, due to shape alone. ASTM C780 indicates that the cylinder specimen strengths are about 85% of cube compressive strengths.)
Proper molding, handling, and curing techniques are used in preparing test specimens.
Often test results are lower than expected simply as a result of careless application of test procedures.
Significance of Test Results
In addition to the related variables noted in Table 1, test results are affected by inherent variations in the procedures and the technique used by the person performing those procedures. Clearly, methods that have fewer contributing variables are generally more desirable for quality control testing. Test methods that are affected by a complex combination of factors (such as compressive strength)
In-place performance of masonry can better be evaluated from results of masonry assembly tests than from test results of component masonry materials.