Concrete and Block

1. Concrete and Block

2. Technical Lesson Outline • 1. Mortar • A. Must be chemically stable, resist rain penetration, and damage by freezing and thawing. • B. Must have sufficient strength to carry all loads applied to the wall for the life of the building with a minimum of maintenance. • C. Consists of portland cement, hydrated lime, sand, and water. • D. May be purchased in bags of 1 cu. ft. with the proper proportions of lime already added to the portland masonry cement. • E. Consistent mortar color in successive batches is easy to obtain when using masonry cement.

3. Technical Lesson Outline • 2. Recommended mortar mix • A. For ordinary service use 1 part masonry cement and 2 1/4 to 3 parts damp, loose mortar sand. • B. For jobs subject to extremely heavy loads, violent winds, earthquakes, or severe frost action use 1 part masonry cement plus 1 part portland cement to 4 2 to 6 parts damp loose mortar sand.

4. Technical Lesson Outline • 3. Mixing procedures for mortar • A. Measure out the masonry cement and sand for a batch of mortar. • B. Mix the materials in a leak-proof box with shallow sides. • C. Stir and mix with a regular mortar-mixing hoe the dry materials to a uniform color before adding water. • D. Add small amount of water and mix the mortar thoroughly until the mortar is pliable and workable. Water should be added to the mix as needed to obtain the pliable and workable characteristic.

5. Technical Lesson Outline • 4. Figuring the amount of materials for job • A. A one bag mix of 1 part masonry cement and 3 parts sand will lay approximately 100 units of 8"x 8" x 16". It takes 112 such units to lay 100 sq. ft. of wall. • B. Example: • Have to lay 525 masonry units 8" x 8" x 16". • How many bags of masonry cement and cubic yards of sand are needed to do this job? (1 part masonry cement and 3 parts sand)1 bag will lay approximately 100 masonry units -1 x 5.25 = 5.25 or 6 bags of masonry cement • For each batch we use 3 times as much sand as masonry cement. • 3 x 5.25 = 15.75 cubic ft. of sand • 15.75 = .6 cubic yds. Of sand • 27

6. Properties ofMortar • Plastic Workable • Uniform Consistent • Hardened Strong • Durable Water Tight • Non- Segregating Economical • Resistant To Abrasion