A concrete cylinder test, also called a cylinder break test, measures the compressive strength of concrete by casting sample cylinders from the delivered mix, curing them, and crushing them in a hydraulic press until they fail. The load at failure divided by the cross-sectional area gives the compressive strength, reported in psi or MPa. Cylinders are cast to ASTM C31 and broken to ASTM C39, and they are the accepted basis for strength acceptance on most North American projects.
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The trade-off is timing. A cylinder tells you what the concrete did under controlled curing, at the age it was broken, which on a 28-day acceptance break means the answer arrives four weeks after the pour. That is the right tool for compliance and the wrong tool for deciding whether you can strip forms tomorrow morning.
How do Third-Party Labs Perform a Concrete Cylinder Test?
There are two types of specimens that field technicians collect to test the strength of concrete (in accordance with ASTM C31):
- Standard-Cured Cylinders
- Field-Cured Cylinders
As the name suggests, field-cured cylinders are subject to the same temperature and relative humidity levels that the completed structure will experience in its environment. Unlike standard-cured cylinders, field-cured specimens are kept right beside the concrete slabs on site. They are predominantly used for determining whether a structure is ready for critical operations like removing formwork, tensioning, and road openings.
In standard or lab curing, concrete test cylinders are sent to the lab and subjected to standard temperature and humidity conditions (23.0 ± 2 °C and relative humidity greater than 95 percent) as outlined in the project’s specifications. They are generally used for quality control and standard acceptance purposes.
Lab Steps
When the specimen (e.g. drilled cores and molded cylinders) is ready to be tested in the lab, the technician follows these steps:
- Examine the concrete cylinders to ensure that there are no defects
- Measure and weigh the cylinders and prepare the samples by grinding or capping the ends
- Place the samples in the hydraulic compression testing machine and carefully align them with the loading axis
- Allow the machine to compress the sample until it splinters or breaks
- Record the compressive strength and type of failure
The cylinders are then tested usually 3 days, 7 days, and 28 days after field installation to determine the concrete’s compressive strength. Sometimes, tests will also be carried out at 24 hours, 14 days, or 56 days depending on the project specifications.
Want to learn more about what concrete curing is? Read this blog
Concrete cylinder test: pros and cons at a glance
| Factor | Where cylinder testing works well | Where it costs you |
|---|---|---|
| Acceptance and compliance | Standardized under ASTM C31 and ASTM C39 and accepted by specifiers, owners, and building officials without argument | Nothing. This is the method’s core strength |
| Speed of result | Fresh property results are known on site immediately | Compressive results wait for the break date and the formal report, so the 28-day answer arrives 28 days late |
| Cost per test | Low per break, and qualified labs are widely available in most markets | Costs compound across a large project, and a bad sample means paying twice |
| Sensitivity to handling | Reliable when the technician follows the standard exactly | Poor consolidation, wrong initial curing, or rough transport all produce low breaks that are a sampling problem, not a concrete problem |
| What it represents | A controlled measure of what the delivered mix can achieve | A cylinder cured in a tank is not the slab. Field-cured cylinders get closer, but still sit beside the element, not inside it |
| Schedule impact | Fits well where the pour is not on the critical path | Crews wait on lab turnaround for formwork removal, tensioning, and load release |
Qualified third-party labs are easy to find precisely because the method is so well established, and individual breaks are inexpensive. The cost that hurts is rarely the invoice. It is the waiting, and the reruns.
The Pros of Using Third-Party Concrete Testing Labs
“ASTM C39: Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens” has been in existence for many decades. It outlines specific rules and conditions to ensure that labs properly test concrete samples. As the construction industry’s most utilized concrete compression strength testing method, engineers, project managers, and contractors can trust that it will provide accurate measurements (most of the time).
As long as the procedure adheres to the standard, and test reports are accurate, it’s nearly impossible to falsify the strength of the concrete with this method. For example, fly ash can be added to concrete to improve its strength and durability. However, to cut corners in some cases, material providers replace fly ash with fillers in their concrete mix. In this scenario, the strength of the concrete may meet the industry standard after 24 hours. Yet, thanks to the concrete cylinder test, labs will discover that the strength diminishes to well below the minimum accepted strength after only a few weeks. This gives the construction company the knowledge they need to avoid building a weak structure made of sub-par concrete.
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Why the Cons of Third-Party Concrete Testing Labs Can Impact Your Project
Despite the benefits of using third-party labs for concrete cylinder testing, this method isn’t completely foolproof. There’s a lot of room for improvement when it comes to optimizing the use of resources. This can include: minimizing costs, increasing accuracy, and reducing the time it takes to measure concrete strength.
As everyone in the construction industry knows and has accepted, completing a concrete cylinder test from start to finish is a time-consuming process. Once concrete is poured the cylinders are made by a technician and placed in an adequate curing environment. For standard-cured specimens, they must sit for 8-24 hours before they can be collected and transported to the lab for a break test to be completed.
The desired strength can be reached well before standard curing periods. However, field personnel and project managers still need to wait for labs to complete break tests before they can move on to the next steps in the construction process. This further prolongs deadlines, especially when doing field-cured cylinders.
Test results of fresh concrete are known immediately, at least by the technician. Nonetheless, results for compressive or other hardened properties like flexural strength are not normally available until formal test reports are released. Needless to say, break tests don’t allow for real-time results.
Human Errors are Always Possible
The concrete cylinder testing method isn’t an inefficient method as a whole. However, there has been a considerable amount of “bad” or low breaks recorded. This could be attributed to technicians failing to follow the standard’s specifications rather than the standard itself. For example, if the cylinders aren’t cured in the right way, this can result in a low break. Unfortunately, low breaks caused by human error aren’t the only concern that companies have regarding inaccurate results. There have been cases of labs manipulating and falsifying results. Even for major buildings that see a lot of traffic on a daily basis. Furthermore, there has been documentation of the wrong concrete mix being delivered to the jobsite. This results in even more delays if it’s caught in time.
Case Study: ARW Concrete Contracting
ARW Concrete Contracting experienced a similar issue when they discovered that their ready-mix producer added water to their mix. Read about their experience here.
While individual break tests are inexpensive, these costs add up over time, especially on large construction projects. The costs incurred due to errors made on the part of the field technician or lab also need to be considered. For example, if the field technician fails to properly consolidate the concrete cylinder by rodding the sample or using a vibration machine, it can result in a bad sample. Mistakes can also occur in the lab and during transportation. A lab technician could accidentally allow the perpendicularity of a cylinder’s axis to deviate by more than half a degree, for example. Or, cylinders may not be stored properly during transportation and may cause micro-cracking. This would reduce the overall strength of the cylinder during testing and affect the accuracy of the data.
But before the break tests can even happen, construction companies first need to be able to hire people that want to do the manual labor of filling and transporting concrete test cylinders. Headhunting requires a lot of time, financial resources, and human capital. With the severe labor shortage that the construction industry has been facing, the problem is only getting worse as time goes on.
How Cylinder Testing and In-Place Testing Work Together
Break tests are generally reliable and inexpensive mainly for small to medium-sized projects. However, there are better ways to measure concrete strength that are less costly in the long run. For example, wireless maturity sensors allow for real-time temperature and strength monitoring. They also eliminate the need for time-consuming break tests. Armed with this knowledge at any given time means that contractors and project managers know exactly when their slab is strong enough to begin the next phase of the project.
The practical answer on most jobs is not to replace cylinder testing but to stop asking it to do a job it was never designed for.
Cylinders answer the acceptance question: did the concrete that was delivered meet the specified strength? Keep casting them, keep breaking them at the specified ages, and keep them as the contractual record.
In-place monitoring answers the schedule question: is this element strong enough right now? SmartRock sensors are embedded on the rebar before the pour and log the concrete’s temperature continuously. That temperature history is converted into an in-place strength estimate using the maturity method under ASTM C1074, against a strength-maturity curve calibrated for the specific mix. Because the sensor sits inside the element, the estimate reflects the curing conditions the structure actually experienced, not the conditions in a curing tank across town.
Run both, and each does what it is good at: the cylinders satisfy the specification, and the sensors keep crews from waiting on a result that the concrete reached days ago.
Interested in comparing maturity sensors to other strength testing methods?
Concrete cylinder test FAQ
How long does a concrete cylinder test take? Cylinders are typically cast on site, left to set for the initial curing period, then transported to the lab and broken at ages set by the specification, most commonly 3, 7, and 28 days. Some projects add 24-hour, 14-day, or 56-day breaks. The compressive result is not usable for decisions until the break is done and the formal report is issued.
What is the difference between standard-cured and field-cured cylinders? Standard-cured (lab-cured) cylinders are held at controlled temperature and humidity and are used for quality control and acceptance, because they show what the mix is capable of under ideal conditions. Field-cured cylinders are stored next to the structure so they experience similar site conditions, and they are used for decisions like formwork removal, tensioning, and opening to traffic. They are not interchangeable, and the specification will say which one governs which decision.
Why do concrete cylinders break low? A low break is more often a sampling or handling issue than a concrete issue. The usual causes are poor consolidation when the cylinder was filled, incorrect initial curing temperature in the first day, damage or micro-cracking during transport, poor end preparation, or a specimen that was not properly aligned in the machine. Before concluding the concrete is deficient, the sampling and curing record is what to check first.
How much does a concrete cylinder test cost? Pricing varies significantly by market, lab, and turnaround, so treat that as an order of magnitude rather than a quote. The larger cost on most projects is schedule time spent waiting for results, not the lab fee.
Can maturity testing replace cylinder breaks? It can replace many of them, but not the acceptance breaks unless the specification allows it. The maturity method under ASTM C1074 still requires cylinders up front to build the strength-maturity calibration curve for the mix, and most specifications retain a reduced set of acceptance cylinders. What maturity removes is the field-cured cylinders cast purely to answer “can we strip yet”.
**Editor’s Note: This post was originally published in April 2019 and was updated for accuracy and comprehensiveness in August 2026.
Sources:
Instron
Archtoolbox
The New York Times
Owlcation
Concrete Construction
