Material Testing & Analysis

Material Testing & Analysis

Please refer to our Specifier’s Guide to Mortar Testing for information about specifying the most useful testing procedures

We have partnered with a nationally renowned testing lab to provide a comprehensive range of advanced material and masonry mortar testing, which we supplement with our analysis and replacement recommendations. 

Once the lab has completed the tests and provided a report, we review and analyze the data to identify the original material and make scientifically-based restoration recommendations. In order to make the most accurate restoration recommendations, we’ve run ASTM C-1324 tests on our entire line of historic mortars so we can compare performance characteristics of the original with replacement products and identify the most suitable option.

With the exception of ASTM C-1324, these tests generally have to be performed in some combination in order to yield useful information. We will be happy to work with you to develop the test matrix that best suits your project.

Please allow 3-4 weeks for for most testing procedures. The lead time may be longer during times of peak demand.

ASTM C-1324 "Analysis of Hardened Masonry Mortar"

One of our most commonly requested tests is ASTM C-1324, which is a comprehensive test of historic masonry mortar. This test calculates the cement to hydrated lime ratios as well as sand to cementitious ratios. The lab test results include a written, photodocumented report with limited interpretation. We will review the test results and analyze them to identify the original material and make restoration recommendations.

 

This test 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: 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.

X-Ray Diffraction

Phases are identified by mineral names and chemical formulas. Abundance of phases is estimated as “major,” “minor,” or “trace.” Narrative report includes a table of observed phases. XRD on acid insoluble fraction further characterizes the “sand.”

Acid Digestion

Digests the binder away from the sand to determine sand content. If the mortar is very hard and tested by ASTM C-1324, the sand particles may not be able to be kept intact for digestion, thus sand gradation may not be determinable.  Additional digestion of other, larger pieces of the mortar will be necessary to obtain enough intact sand for a sieve analysis. If carbonate sand is present, the sand volume and sieve analysis will be biased. Thin section analysis will be able to assess the approximate percentage of carbonate.

Brief Microscopial Work

Brief microscopial work to examine the aggregates.

Thin Section Analysis

Thin section analysis uses optical microscopy to determine the general composition of the mortar, binder type, and sand types. This analysis will not determine the actual sand gradation or cement to hydrated lime ratios. The lab results include a written, photodocumented report with limited interpretation which we supplement with our recommendations.

X-Ray Fluorescence (XRF)

XRF yields a one-page report listing the percentages of chemical elements expressed as oxides, SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, Na2O, K2O, TiO2, P2O5, SrO, Mn2O3, ZnO, and Cr2O3. Thermogravimetric analysis is used to calculate hydrated lime and carbonation.

This test is useful for mix reconstruction and mortar matching.

Scanning Electron Microscopy (SEM)

This test can assist in the small-scale determination of the composition of individual particles in the original binder that cannot be detected in bulk analysis or by microscopy. Historical mortars can contain unusual ingredients which may or may not be important in the analysis.

Initial Rate of Absorption (set of 5)

This test can assist in the small-scale determination of the composition of individual particles in the original binder that cannot be detected in bulk analysis or by microscopy. Historical mortars can contain unusual ingredients which may or may not be important in the analysis.

Compressive Testing (Set of 5)

ASTM C-67: This test determines the average compressive strength of a clay brick masonry unit based on 5 samples.

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