Quality Control Tips from PCS

 

Flatwork Placement & Curing Tips

 

1. Choose the correct mix for your project. (Remember: Air mixes are to be used for exterior work. Non-air mixes are recommended for interior work only. Note: Do not hard trowel air entrained concrete as this may cause delaminating and/or blistering!) Always feel free to consult PCS for guidance.

 

2. Properly prepare your sub-grade. For interior concrete - place your vapor barrier down first (plastic) then put down your base (typically 2 inches of CR-6 or stone dust). Placing concrete directly on plastic may cause delaminating and/or curling!

 

3. Wet down your sub-grade. Placing concrete on a dry sub-grade will cause the sub-grade to actually absorb all of the water out of the concrete - thus causing cracking!

 

4. Do not add excessive water to your mix! Standard mixes are designed to reach a maximum 5" slump. Exceeding the proper slump by adding too much water to your mix can create many problems such as decreased strength, decreased durability and cracking.

 

5. Need a higher slump? Order a High Range Mix! Mixes containing High Range (AKA: Super P) will allow you to pour between a 5” and 8" slump without affecting the integrity of the concrete! The increased slump is strictly due to the chemical inducement of the high range and will not only increase workability, but results in a better product!

 

6. Do not use a garden rake to spread your concrete. Use your square edged shovel or a come a long. Garden rakes will cause the concrete to segregate.

 

7. Tamp your concrete along the edges of the forms to release air voids.

 

8. Do not pre-maturely finish or over finish the concrete. Allow the concrete to finish "bleeding". Using the bleed water to finish and/or over working your concrete surface may cause a multitude of problems - including dusting.

 

9. Use your wind barriers! Winds of 5 mph or more can cause cracking!

 

10. Protect your freshly placed concrete. We strongly recommend that you apply a curing compound or better yet, a cure and seal product as soon as you have completed the job. A cure and seal product (which can be purchased at your local hardware or concrete store and applied with a sprayer and/or as per manufacturer recommendation) will ensure proper curing as well as aid in protecting your concrete from staining and most importantly - scaling! Important note: Be sure the product is a Cure and Seal as a regular sealer does not allow the concrete to breathe (cure) and may only be used on mature concrete!

Cure and Seal for lasting appeal...

Concrete surfaces are very porous and therefore will readily absorb foreign substances causing unsightly staining. The use of cure and seal on your flatwork surfaces will result in a protective barrier against spills on your surface. While sealing the surface will not totally prevent staining, it will make it much more resistant, as well as increase your chances of being able to clean it up. On another note, sealing pigmented concrete will intensify its beauty, especially if you have stamped concrete. Has your existing stamped concrete lost its luster? Clean it up and seal it, you will bring it right back to life. In many cases, it will look new again.

How to reduce shrinkage cracking

Concrete shrinks during the hydration process. This process typically causes cracking, especially in pea gravel mixes due to their high water contents. The best way to reduce shrinkage cracking is with fiber reinforcement. Small fibers are added at the time of batching to reduce shrinkage cracks and improve durability. ASK our dispatch about adding fibers to your order.

CURING

“Properly curing your freshly placed concrete is just as important as following all standards and specifications for placement! Curing your concrete properly will aid in strength gain, reduce cracking, improve durability and improve appearance.” Please call us for more tips on curing your concrete.