In its simplest form, concrete is a mixture of paste and aggregates (i.e. sand & rock). The paste, composed of cement and water, coats the surface of the fine (sand) and coarse aggregates (rocks) and binds them together into a rock-like mass known as concrete.
Within this process lies the key to a remarkable trait of concrete: it's "plastic" and can be molded or formed into any shape when newly mixed, yet it is strong and durable when hardened. These qualities explain why one material, concrete, can build skyscrapers, bridges, sidewalks, superhighways, houses, streets, and dams.
The key to achieving a strong, durable concrete rests on the careful proportioning and mixing of the ingredients. A concrete mixture that does not have enough paste to fill all the gaps between the rocks will be difficult to place and will produce rough, honeycombed surfaces and porous concrete. A mixture with an excess of cement paste will be easy to place and will produce a smooth surface; however, the resulting concrete will be more likely to crack.
Cold Weather Concrete
Placing concrete in cold weather often involves heating some of the concrete ingredients, protecting the freshly-placed concrete from freezing, and…
Proper fabrication, care, and curing of concrete test cylinders is critical for the results to be valid and meaningful.
Concrete is one of the most versatile building materials, and can be made to look like almost anything else.
Ready mixed flowable fill is commonly referred to as controlled low strength material (CLSM).
Ready mixed flowable fill is…
Hot Weather Concrete
Placing concrete in hot weather might mean cooling materials or placing concrete at nighttime to avoid daytime extremes.
Checklist For Pre-Job Site Inspection
1. Has the sod, topsoil and vegetation been removed?
All organic material must be removed before paving operations are…
Concrete Placing, Finishing and Texturing
A uniform thickness of concrete (according to the design) should be placed on the prepared subgrade, adequately consolidated, and struck…
In general, concrete should be mixed and delivered according to the requirements of ASTM C94, "Standard Specifications for Ready Mixed…
Curbs should be constructed at the location shown on the plans. Curb and gutter can be constructed separately from the…
Immediately after texturing, cover the surface with a white pigmented curing compound complying with ASTM Specification C309 (at the rate…
Concrete parking lot pavements should be plain, non-reinforced concrete built in accordance with the specifications.
The pavement should be jointed to control cracking. The joint lay out, compatible with the contractors paving method and equipment,…
Opening to Traffic
Pavement under construction should be protected with barricades and all traffic (with the exception of joint sawing equipment) for seven…
The contractor is responsible for concrete placed during rain or cold weather and any concrete damaged by rain or low…
Slab depth for parking lots should be as shown on the plans.
Recommended parking area slab depths, based on…
The goal is to place concrete parking areas on properly prepared subgrades that are uniform in soil composition and compaction.…
When it rains, it drains.
Pervious concrete is a concrete mix that has minimal sand (fine aggregate). Due to…