Mortar Testing Services

AMR Labs
817-366-8376
MortarLab@gmail.com 

You can send samples of hardened mortar for testing to us at the following address.

AMR Labs
1525 Corona Dr.
Granbury, TX 76048

We are making brick mortar cracks disappear. - AMR

AMR Labs is dedicated to matching mortar.
This is why we offer various forms of matching mortar including mortar analysis, mortar testing, sand analysis, mortar composition testing, and custom mortar color matching.

Click here to order/get prices and procedure for mortar testing.

Mortar Testing

AMR Mortar Testing Services
AMR Labs provides mortar testing services to analyze samples of hardened mortar in an effort to determine the properties and composition formula of old existing mortar from masonry walls and structures to improve the accuracy and durability of mortar repair, or to compare samples of mortar.

Mortar Testing Labs

Mortar testing labs are useful in determining the quality of mortar, testing physical properties of mortar, and identifying mortar compositions and ratios. This is especially important when restoring or preserving historical mortar.
However, not all mortar testing labs are the same. Most testing facilities are designed for materials testing of new materials, and test mortars for new construction. These would include the astm C-270 and C-290 testing of mortar. While these work great for testing new mortar, they are limited in testing old existing mortar samples because they require testing at 14 days and 29.5 days of curing. Some mortar testing labs have began offering different mortar testing methods to better serve the mortar repair needs by providing one or both of the most common mortar testing procedures. However, without an understanding of cement or lime mortars in their use and how they act over time, interpreting the results of these tests often allows large room for errors.
We are an independent mortar testing lab, and focus on testing existing mortar and matching old mortar compositions and ratios. While we can provide compressive strength testing of mortars and other tests of new mortar, our testing lab is designed for testing and matching old and historic mortar.

Testing Mortar Samples

Testing Mortar Samples
When testing hardened mortar samples from existing masonry structures, there are two commonly used methods for determining the composition ratio of the original mortar formula. They are the acid digestion mortar analysis and the astm C-1324 mortar test that is discussed in the preservation brief which uses a spectrographic analysis.
These forms of mortar testing provide unreliable results due to their particular limitations. The biggest limitation to the reliability of these mortar testing procedures is the amount of data collected during the mortar analysis, and the amount of experience each mortar analyst has in both testing mortar and more importantly field use of mortar. In order to understand the results you must understand mortar and how it is used including why the different components are added to the mortar and what they do.

Mortar Testing Procedure

Mortar Testing Method
With an understanding of mortar and the limitations of these mortar testing methods, AMR Labs developed a proprietary mortar testing procedure for analyzing samples of old mortar to determine their composition ratio and formula, and provide accurate and reliable mortar matching.
During analysis, mortar samples are tested for their compressive strength, visual analysis under magnification, acid digestion, weight loss, and a visual or sieve analysis of the sand gradation and particles. This is all part of the mortar composition testing.
AMR Labs is an independent mortar testing lab and provides a proprietary mortar testing method that includes several astm testing methods including C-109 crushing analysis, acid digestion, and E-11 sand sieve analysis. However, in our proprietary mortar testing method, we collect additional data that is generally over looked in these tests and combine these results with some scientific mortar testing methods to provide better results than other mortar testing methods can provide.

Testing And Matching Mortar Composition

Mortar Composition Testing/Analysis

When creating a matching mortar for repair or tuckpointing, it is essential to match the mortar type and crushing pressure of the existing mortar. The best way to match mortar is through testing mortar to find the composition and ratios of materials.
Mortar composition testing is done by an analysis of mortar samples. This detailed mortar analysis includes a physical examination of the mortar sample looking for noticeable points of interest (hair, plant fiber, larger aggregate, or large lime particles), testing properties of the mortar (compressive strength of mortar sample/crushing analysis), magnified examination of pulverized or crumbled mortar sample, measure the weight of the sample mortar and begin chemical testing or acid digestion of the crumbling mortar sample, drying and re-measuring the remaining weight of the sample, determine weight loss amount and ratio, basic separation and analysis of the sand (you can add a detailed sand analysis using E-11 specifications for sand sieve testing), calculated and interpreted results.
This last portion of the mortar composition testing is where we use some of the additional data collected during analysis to determine and validate mortar type and composition formula ratio. This is done by using the compressive strength, the shape and size of aggregates, the amount of weight loss, and the weights of identified binder materials in the mortar sample tested. Through testing and calculating these details, we identify the probabilities of mortar formula ratios, and are able to eliminate the ratio formulas that don't agree with the known properties of the mortar sample (crushing pressure, known binders, gradation of sand, etc.). Result accuracy is within 0.01g.

Compressive Strength Testing

Testing the compressive strength of mortar samples helps to identify the mortar type and how a replacement mortar will need to perform in order to bond to the original mortar existing in the masonry wall. While this portion of the composition testing is not always possible with old historic mortars or crumbling mortar and we can still identify mortar composition without it, it is preferred and very helpful to include this test of the mortar sample. So, please try to get at least some small pieces of solid mortar.
Compressive strength testing is included in the mortar analysis, but you can add an additional compressive strength test for masonry unit testing if needed, or add this test to a color match for a quick match of mortar type based on performance or crushing pressure.

Acid Digestion Mortar Analysis

Breaking down the mortar sample with acid during the acid digestion testing method allows us to identify certain binder materials by their reaction with the acid and determine to amount of binder material within the mix. This process is complimented with the sand analysis and weight loss. In addition, acid digestion of the mortar mix cleans the sand for examination.

Sand Sieve Testing

The sand analysis provides detailed information about the original sand used. This includes a gradation analysis of the sand particle sizes, color description of particles, and identifies the shapes of sand particles used. Through this analysis, we are able to provide recommendations of quarried sand or river sand particle distributions.
Add this test to the composition analysis testing to get a more detailed composition formula with more information about the original sand used in the mortar mix and the ratios of graded particle sizes and their colors.

Testing Crumbling Mortar and Historic Mortar Samples

Testing Crumbling Historic Mortar

Historic Mortar Testing
Testing historic mortar samples can be a little different than the mortars today because of the amounts of Portland cement used. Portland increases the crushing pressure and reduces the water penetration of the mortar.
While some Portland was used in many historic mortars in smaller amounts than newer mortar, historic mortars tend to be lime based or lime mortar. These lime mortars, type k mortar, and type o mortar mix range from about 75 psi up to about 350 psi compressive strength, and the softer mortars tend to crumble. This is especially true when you are attempting to collect the mortar sample for testing.
Don't worry, we can still test crumbling mortar, but it is best if we can get some larger pieces for matching. We will need about a cup or more of mortar for testing, or a few larger pieces. It is better if you can send more sample mortar in case we need to retest, and larger samples provide better or more accurate results.

Custom Brick Repair Mortar

Custom Brick Repair Mortar
If you are needing small portions of mortar custom made to the formula determined during testing, we can produce boxes of custom mortar mix. If you add a color match to your analysis of the composition, we can adjust color tones as needed.
For larger volumes of mortar, it will likely cost less to buy the base materials and follow the formula onsite or send the formula to a manufacturer. Virginia lime always provided good service for our historic lime mortar customers, but you could try US Heritage Group or limeworks.us, or for newer mortars (using type S/SA lime) you can get materials at your local masonry supply.