When monitoring the strength of in-situ concrete, the most common method that is used today is field-cured cylinders. This practice has remained largely unchanged since the early 19th century. These samples are casted and cured according to ASTM C31 Standard Practice for Making and Curing Concrete Test Specimens in the Field and tested for compressive strength by a third-party lab at various stages. Knowing the rate at which your in-situ concrete is gaining strength informs you about when you can move to the next stage of your project. Usually, if field-cured specimens have reached 75% of its designed strength, engineers will give the ‘go ahead’ to their team to move on to these next stages s in the construction process, such as post-tensioning or removing formwork.
Unfortunately, field-cured cylinders are prone to inaccuracies. In particular, it is very difficult to maintain the specimen in the same curing conditions as your in-situ concrete, especially in extreme weather. For this reason, alternative methods for testing concrete strength are becoming more common, especially as new technologies penetrate the construction industry. One such alternative technique is the maturity method.