Minnesota’s weather and temperature fluctuations can be very tough on the surface of exterior concrete. We’ve produced a guide, located below, on the best practices for placing concrete in our area, as well as other considerations to make. Remember, we’ve been working with concrete in Minnesota since 1936, and we are here to help you!


Make sure your using the best mix for your application. There are certain materials one is required to have on hand, and we’ve made a checklist of those materials and put that down below.

  • Concrete with a minimum of 6% air entrainment.
  • Make sure your supplier uses ASTM materials and produces properly portioned mixes with industry accepted quality assurance.
  • Maintain a water-to-cement ratio at or below .45


Several years ago, Minnesota experienced an unusually high number of jobs with surface defect issues. In an attempt to understand what caused the surface defects, Marshall cored and tested dozens of jobs with surface defects. In almost every case, the concrete below the top surface of the slab was of high quality and could be expected to provide years of durable service.

However, the surfaces of the core samples told a different story. The surfaces showed at least one of the following:

  • Ineffective curing (or no curing at all)
  • Trapped bleed water
  • Excessive surface density causing loss of air entrainment at surface (steel troweling)
  • Higher water cement ratios on the surface.

We suggest following these practices to avoid those problems:

  • Provide sufficient slope for drainage (1% minimum, 2% preferred)
  • Do not over-finish the surface.
  • Do not finish with steel tools.
  • Cure the concrete promptly and properly.
  • Place driveways before October 15.
  • Avoid the use of deicers in the first winter of service

Cures & Sealers

All driveways in Minnesota should be cured as soon as the last finishing operation is completed.

Few topics cause more confusion for users of concrete than curing and sealing. We want everyone using our products to understand these vital steps in the concrete construction process.

Concrete is a mixture of cement, sand, coarse aggregate, water and admixtures. When the cement comes in contact with water, a chemical reaction called hydration occurs. It is this chemical reaction that changes concrete from a fluid to an inflexible, strong, stone-like substance.

Cement hydration is a long term process. After 28 days, 95% of the hydration is completed, so the concrete has gained most of the compressive strength that it will achieve. However, for hydration to continue for 28 days, two conditions must be maintained:

  • Sufficient temperature (above 50 degrees F.)
  • Sufficient moisture

If either of these conditions is not maintained, hydration will stop, and concrete will stop gaining strength at that time. Curing is maintaining sufficient moisture and temperature for hydration.

Sealing is applying surface protection on cured concrete. Sealing should occur 28 days after the concrete is placed. For exterior applications, especially areas exposed to road chemicals, sealing should be repeated every 3-4 years with high quality sealers. We have a full line of curing and sealing products available to protect your project.

Curing Methods

  • Air Cure – this means no cure at all – this method is okay for a footing or a basement floor perhaps, but not too smart on a driveway or exterior concrete project.
  • Water Cure – must keep concrete saturated – allowing it to dry out stops hydration
  • Membranes – poly will leave discoloration. Kraft paper is a two part system – wet under layer and poly outer layer.

Chemical cures – spray on chemicals – water based or solvent based.

Further Reading:

We realize that our products are used for a variety of projects including sidewalks, decorative paths, pools, etc. Here are some additional practices to keep in mind when working with concrete in general no matter what the projects is.

  • Place concrete on damp sub-grades (never place on standing water).
  • Insure that screeding knocks rocks down below the surface.
  • Pay attention to environmental factors like heat, wind, humidity and sun.
  • Be prepared to protect the surface from rapid drying – have evaporation retardant on hand and/or erect wind shields to prevent rapid surface evaporation.
  • Use super plasticizers instead of water when more workability is desired.
  • Avoid trapping bleed water and prevent incorporating bleed water back into the slab.
  • Don’t place more than your crew can handle.
  • Avoid adding water to the surface of the concrete during finishing.

Common Concrete Surface Problem Definitions:

Popouts – deleterious material in aggregate absorbs moisture, freezes during the winter, expanding and “popping” off the top surface. A small crater remains in the surface, and the remnants of the soft, deleterious material are still in the crater. Common issue with gravel mixes. Once the soft aggregate has popped, no further damage will be done to the slab.

Mortar Flaking – the surface layer of paste peels off the slab, leaving a sound piece of aggregate exposed. this is a Common problem with granite mixes if the curing was ineffective. Usually limited to areas immediately above a submerged piece of non-porous, flat aggregate. Damage often limited to a few spots where aggregates were close to the surface.

Scaling – top surface peels off the slab. Typically not an aggregate problem. Caused by too much water in the mix, lack of curing or water added to the surface and troweled back in while finishing. Slab must be carefully assessed to determine if the problem is limited to the surface or if the entire slab is compromised.