Construction Principles Final Exam

admixtures

-Added ingredients to improve performance or adjust properties: -Pigments, colored aggregate -Bond enhancers: Improve flexural strength, freeze-thaw resistance -Set accelerators and retarders: Adjust setting time in cold or hot weather -Water repellents: Improve water resistance -Workability enhancers: Ease placement of wet mortar

Portland Cement

-Calcium silicates -Calcium from limestone, marble, and other minerals -Silica from clay, sand, shale, marl -Very fine particle size: 0.0004 to 0.0006 inches diameter

Water

-Clean, neutral pH, free of contaminants or organic material -Potable water is generally considered suitable.

Aggregate

-Natural Sand -Manufactured sand made from crushed stone, gravel, or furnace slag -A well-graded mix with particles ranging in size from 0.003 - 0.187 inches in diameter

Hydrated lime

-Quicklime: Limestone and other minerals are finely ground and heated to produce calcium and magnesium oxides: CaO/MgO. -Sufficient water is added to quicklime to slake or chemically convert the oxides to hydroxides: Ca(OH)2/Mg(OH)2. Hydrated lime remains a dry powder.

Mortar Mix

-Sand provides the basic structural body of the hardened mortar. -There is almost one cubic foot of sand in a cubic foot or mortar -Cement is the glue that binds the sand particles together. -Lime improves the workability of mortar in its plastic state. -A minimum amount of water is necessary for the chemical hydration of the cement. -Additional water is added to produce a god working consistency to the wet mortar.

ingredients of Portland Cement-Lime Mortar

1. Portland cement 2. Aggregate 3. Hydrated lime 4. Water

Hydraulic Cement (portland cement is one)

It hardens by chemically combining with water—hydration; Lesser quantities of compounds of iron, aluminum, magnesium, and sulfate improve the hydration process

Stone and brick masonry

the strongest and most durable of pre-industrial building materials

Mortar

Cushions masonry units, ensuring uniform bearing Seals joints between the units, minimizing the flow of air and water; Adheres units, providing resistance to lateral forces from wind, earthquakes