Mortar Testing & Analysis
We have partnered with a nationally renowned testing lab to provide a comprehensive range of advanced masonry mortar testing services:
Material Testing
We have partnered with a nationally renowned testing lab to provide a comprehensive range of advanced masonry mortar testing services.
ASTM C-1324 Standard Test Method for Examination and Analysis of Hardened Masonry Mortar
This comprehensive mortar testing procedure includes two primary procedures:
Petrographic examination will be performed on split portions of the sample in accordance with Section 8 of ASTM C1324 to document the mineralogical and physical characteristics of the mortar and describe the mineralogical constituents used in the mortar mixture. Mineralogical constituents usually include aggregate and mineral-based, hydraulic and non-hydraulic constituents of the cementitious binder.
The petrographic examination will include the production and examination of petrographic thin sections of representative pieces of provided mortar. Findings of the petrographic examination will provide information that will be referenced and used in the chemical analysis, including mineralogical features in the mortar that may pose potential interferences with the chemical analysis methods, such as acid soluble components in the aggregate that may go into solution upon the chemical digestion of the sample(s).
Chemical analysis will be performed on split portions in accordance with procedures and guidance provided in ASTM C1324. Representative portions of each mortar will be ground and chemically digested, then analyzed to determine the concentrations of certain soluble and insoluble constituents.
From these findings, and information provided by the petrographic examination, the volume proportions of these constituents are calculated.
One important note: one of the most common problems we encounter are specifications that call for testing the compressive strength of mortar. While ASTM C1324 provides data on the composition and volumetric proportions of mortar, there is no ASTM standard test to determine the compressive strength of an extracted historic mortar sample. The standard test for compressive strength is ASTM C-109 “Standard Test Method for Compressive Strength of Hydraulic Cement Mortars” which involves compression testing a set of two-inch cubes. This procedure doesn’t translate to smaller, irregular samples pulled from a wall, nor does it account for the numerous other variabilities of extant historic mortar.
Some testing facilities offer compressive strength testing for historic mortars but such proprietary tests rely on undisclosed methods, meaning that the results can’t be independently verified or analyzed and it’s impossible to determine how sound the methodology is.
ASTM C67 “Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile”
Understanding the characteristics of the masonry units themselves provides a framework for selecting mortar. The goal of the mortar is to cushion the masonry units and to transfer moisture out of the wall, and in order to do this, the mortar must be lower in compressive strength and more vapor permeable than the masonry units and the existing mortar. ASTM C67 tests are often specified in conjunction with mortar testing to aid in the selection of replacement mortar and/or to identify causes of masonry deterioration.
This test determines the average compressive strength of a clay brick masonry unit based on 5 samples.
The amount of water absorption is determined by the gain in weight of a dry brick on immersion in water under specified conditions. Water absorption obviously increases as the amount of porosity increases since there must be voids (pores) for the water to be absorbed in or enter into the body of the brick. The results are based on a set of 5 samples.
The amount of water absorption is determined by the gain in weight of a dry brick on immersion in water under specified conditions. Water absorption obviously increases as the amount of porosity increases since there must be voids (pores) for the water to be absorbed in or enter into the body of the brick. The results are based on a set of 5 samples.
NOTE: These are destructive tests that require masonry units that have been removed from the building.
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