How to Troubleshoot Concrete

Rub your bare hand across the concrete to feel for bumps, powder, dings or cracks. Blistering, or the formation of raised bubbles, may be identified this way. Blistering is caused by air being trapped during the finishing process. Powder on the concrete indicates the concrete mixture may have contained too many refined materials. Dings are known as "popouts" and are typically caused by improper mixing of concrete. Cracks require further investigation.

Scrape the concrete with a putty knife. If the concrete flakes off, scaling or spalling may be the problem. Scaling is typically a result of a freezing and thawing cycle over time. Spalling may be the result of poor mixing of the concrete, resulting in the thicker concrete rising to the top and flaking off.

Look at the concrete in direct light. General spots of discoloration may be the result of poor-quality concrete or external factors, including rugs or mats holding moisture on the concrete. Discoloration in lines may indicate shrinkage. Shrinkage is caused by moisture in the concrete rising to high temperatures.

Clean the debris from cracks and identify the contents. Lack of debris indicates pressure cracking. Small pieces of concrete indicate poor slumping or mixture.

Sample the concrete for analysis. Contact the appropriate lab for a sampling kit, and follow the directions. The test analyzes the makeup of the concrete and troubleshoots whether it was a mixing or recipe issue. The results of the test, along with the physical indicators, should give the answer to what is wrong with the concrete.