- Concrete slabs home
- Before you begin: Avoid these 7 common mistakes
- Make sure the subgrade is compact
- Use a low water-cement ratio: How to calculate
- Subgrades and subbases for concrete slabs: Tips for ensuring good support
- Concrete Slab Finishing Tips
- How to Prevent Cracks
- Important guidelines for preventing cracks in concrete slabs
- Be active in deciding where control joints will be placed
- Proper Curing of Concrete Slabs
- Properly curing concrete slabs: Why and how
- Allow enough time to water cure
- Related Information:
- Concrete fasteners
- Concrete forms
- The three types of concrete foundations
- Aggregates in ready-mix concrete
- Vapor barriers for concrete slabs
- Post-tensioned concrete slabs
- Concrete slabjacking
- Concrete testing
How To Build High Quality Slabs on GradeA concrete construction primer on what it takes to build concrete slabs- from proper subgrade preparation to adequate curing
Concrete slabs are used to support everything from patio furniture, to foot traffic, to semi-trailer trucks. With such a wide range of purposes and support requirements, concrete slabs present many construction variables that must be considered before concrete placement begins.
A slab pour requires efficient planning so that all of the elements that go into producing a high-quality slab are done in time (before the concrete sets) and done correctly. Knowing the right finishing tools to use and the right time to start bull floating and final troweling are essential to preventing dusting, scaling and craze cracking of the slab.
You also need to provide a firm and stable base for the concrete slab by compacting the subgrade properly. Neglecting this critical step can result in serious slab settlement and cracking problems, especially in slabs placed on poor subsoil or exposed to heavy traffic conditions.
Determining the right concrete mix design and reinforcement requirements for the anticipated slab exposure and traffic conditions is essential as well. You’ll need to calculate the proper water-cement ratio and air-entrainment requirements for the concrete mix to ensure that the slab will perform as intended. Proper positioning and support of wire reinforcement is also important to control and minimize cracking.
After concrete placement, you have a whole new set of issues to address, such as proper placement and spacing of control joints and adequate curing. The timing and execution of these post-pour activities are equally essential to good slab performance, since rapid drying of a slab and improper installation of control joints can lead to inadequate strength and unwanted cracking. Concrete that is moist cured for at least seven days is about 50% stronger than uncured concrete.
Here are some useful links to information that can guide you through the steps required to build high-quality concrete slabs on grade and help you avoid mistakes that can lead to poor performance, or even worse, slab failure. You’ll also find advice on concrete mix design and calculating the water-cement ratio.