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Concrete & Masonryaka: OPCaka: ordinary Portland cementaka: Type I cement

Portland Cement

In Plain English

The most common type of cement — the gray powder that is the key ingredient in concrete and mortar.

Definition

The standard hydraulic cement used as the primary binding agent in concrete, mortar, and grout, produced by burning limestone and clay at high temperatures and grinding the resulting clinker with gypsum. It was named for its resemblance to Portland stone from England. There are five ASTM types (I through V) with varying properties for different applications and environmental exposures.

Why It Matters in Bidding

The ASTM cement type specified affects both concrete pricing and schedule: Type III high-early-strength costs more but speeds form-stripping cycles, while Type V sulfate-resistant is required for aggressive soils. Estimators rely on the ready-mix supplier's mix-design pricing per cubic yard, and a spec calling for a special cement type or low water-cement ratio can raise the unit price meaningfully across a large concrete pour.

Example

Reviewing the structural notes, an estimator confirms Type II cement for the foundations exposed to moderate-sulfate soil and requests an updated price per cubic yard from the ready-mix supplier reflecting that mix design.

Related Terms

Frequently Asked Questions

Each ASTM type carries a different mix-design cost. Type III high-early strength accelerates form turnover and schedule but costs more; Type V resists sulfates for aggressive soils. Estimators price the specified type per cubic yard through the ready-mix supplier, since substituting a cheaper general-purpose cement risks spec rejection.
Usually no. On most projects concrete is bought as ready-mix priced per cubic yard, with cement bundled into the mix design. Cement is priced as a separate bagged material mainly for masonry mortar, grout, small site-mixed pours, or where the spec dictates a particular cement type and supply.
Specified compressive strength, water-cement ratio, cement type, and admixtures all shift the supplier's per-yard price. Higher strength, low w/c ratios, or special cements increase cost. Estimators send the spec to the ready-mix plant for a project-specific quote rather than using a generic price, then add placement, pumping, and finishing labor.

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