Architectural concrete refers to a building that uses concrete for an aesthetic finish as well as structural fabrication. Concrete can take almost any form, texture, and color to satisfy the aesthetic and functional requirements of architectural concrete-it offers surfaces that range from smooth to rough and a spectrum of color that ranges from the icy blue of quartz through the delicate pastels to the deep reds of decorative aggregates.

Architects consider many factors when selecting color and texture for a concrete structure. The surface area, the viewing distance, the angle of the building wall, and aggregate particle shape and surface characteristics all need to be considered when selecting a texture. When choosing a color, designers must consider that the color will change continuously throughout the day, and that the surroundings of the building will affect the color tone. Color selection should be made in lighting conditions that simulate the environment of the planned structure.

White portland cement is recommended wherever white or colored concrete is required. White portland cement is made of selected materials that contain negligible amounts of iron and manganese oxides-the materials that give cement a gray color. However, white cements have different inherent color tones that architects should consider in the design process.

Integrally colored concrete is made by adding mineral oxide pigments to concretes made with either white or gray cements. White cement is used when lighter shades of concrete are desired, but red, tan, and dark gray hues can be produced using gray cement.

An exposed aggregate surface is a decorative surface obtained by removing the outer skin of mortar and exposing the coarse aggregate. This may be done by sandblasting or using a chemical wash. Selection of aggregates is based on color, hardness, size, shape, gradation, durability, availability, method, and degree of exposure and cost. Popular decorative aggregates are natural materials such as quartz, granite, marble, limestone, and gravel and manufactured materials such as glass and ceramics.

Forms and form liners can be used to create textures and patterns that simulate brick, stone, and wood. Aluminum wall forming systems are available with brick-pattern faces, or with vertical rib or board and batten patterns. Also, a textured concrete surface will help camouflage the subtle differences in texture and color found on the surface of concrete.

Information provided by the Portland Cement Organization.