Mix Design Fundamentals: Considerations for concrete for slabs-on-ground

Photo © BigStockPhoto/Theerapol Pongkangsananan

Interior concrete should not crack or curl excessively requiring grinding before the flooring can be installed; exterior concrete should not crack or deteriorate prematurely from freeze-thaw cycles. Some argue concrete will always crack, and nothing can be done about it. This is most often an excuse when poor design or poor placement has resulted in excessive cracking or the real problem is too much mix design water, lack of welded wire reinforcement, or too little aggregate and poor curing methods.

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Defining and Refining Polished Concrete

Hiperfloor premium reflectiveHC550-0142

French-American architect Paul Philippe Cret once said, “Of the many doorways we pass in a short walk, most are fulfilling their purpose, most of them are well-enough built. [But] how many are worth a second look?” Cannot the same be said about architectural polished concrete? Are your floors meeting your design intent or did you settle? Do you know how to distinguish between the floor you asked for, and the floor being presented to you during the punch list?

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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.

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Out of Sight, Not Out of Mind: Specifying thermal insulation below-grade and under-slab

All photos courtesy Insulfoam

Balancing performance and cost for insulation installed on below-grade foundation walls and under floor slabs can require specifiers to rethink common assumptions about rigid foam insulation. Misperceptions about the moisture absorption of expanded polystyrene (EPS) compared to extruded polystyrene (XPS) may be limiting more cost-effective choices. Test results demonstrate the long-term durability and moisture resistance of EPS insulation and the stability of its thermal performance. In many applications, substituting a strong and adequate, yet lower compressive resistance insulation, can result in significant cost savings.

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