03 30 00 Cast-in-Place Concrete

Category Archives: 03 30 00 Cast-in-Place Concrete

How Thin is Too Thin?

Typical flat-plate construction. Photos courtesy SGH

Evaluating slab thickness in reinforced concrete flat-plate construction
by Dimitri Papagiannakis, PE

 

Reinforced concrete flat-plate construction is popular among mid- and high-rise residential construction projects. It provides a great deal of flexibility in the placement of the structure’s vertical load-carrying elements (i.e. columns and walls) without sacrificing the efficiency of the floor framing—as could potentially be the case with steel or masonry.

In the project’s early stages, structural engineers are often asked by …

Read More

Specifying Steel Fibers for Concrete Floors

Photo © BigStockPhoto/Jacek Sopotnicki

Thin, short strands of steel are being increasingly specified as reinforcement in ground-supported slabs and in composite steel deck-slabs. Structural engineers are still figuring out how best to design with these components, but specifiers need to think about how to define this material in the contract documents. Dosage is critical, for one thing, but not all fibers are alike. Without specifying other key details, one can end up with concrete that contains the specified mass of fibers, but does not fulfill the designer’s intentions.

Read More

Designing Plaza Hardscapes: Considerations from insulation and waterproofing to structural support

Untitled-1

Plaza construction typically incorporates various products from different manufacturers intended to provide the thermal resistance, water management, structural capacity, and wearing surface needed to meet a particular project’s requirements. This article discusses the importance of evaluating the strength and stiffness characteristics of a plaza system, particularly when heavy loading is anticipated. Designs that do not properly account for overall system strength and stiffness are vulnerable to damage, potentially resulting in cracking and displacement of the hardscape materials, reduction of drainage capacity, and reduced service life of the plaza.

Read More

Better Concrete Starting at the Finish: Long-term benefits of colloidal silica-based finishing

Images courtesy Lythic Solutions

Recently, concrete contractors have started using a colloidal silica-based compound as a finishing (or ‘troweling’) aid for flatwork. It makes the surface denser, and increases the quality of cement paste. Additives in the compound help the surface slow evaporation though hydrophobic properties, protecting the concrete from a range of moisture loss-related defects. It also makes it unnecessary for contractors to add water to finish the concrete. The result has implications for buildings, pavements, roadways, bridges, and even precast structural and architectural concrete.

Read More

Standardizing Concrete Polishing

Photo © Chris Rains, Ardor Solutions

Economical, durable, and aesthetically pleasing, polished concrete floors are no longer a novelty as they are continually used for industrial, commercial, and residential projects. What has not become standard is a set of unified terms or policies that might aid in their specification and in the communication between contractors, architects, and owners—this could have adverse consequences with regard to the equipment and/or processes used to construct a floor in the field.

Read More