Arkansas Masonry - Commercial Exam

Key Concepts

What construction drawings are. Construction drawings describe the size, shape, location, and specifications of the elements of a structure; they may also be called working drawings, prints, blueprints, or plans (Modern Masonry, Ch. 5.1, Print Reading).

The Alphabet of Lines (Modern Masonry, Ch. 5.2, Figure 5-1): - Border lines — very heavy; form a boundary and assure the reader no part of the drawing has been removed (5.2.1). - Object lines — heavy; show the outline of visible features: walls, windows, patios, roof lines (5.2.2). - Hidden lines — medium-weight; an edge or intersection of two surfaces not visible in a given view (e.g., foundation wall and footings on an elevation, because they are below grade). Usually not as thick as object lines (5.2.3). - Center lines — thin; indicate the center of symmetrical objects (5.2.4). - Extension lines — thin; show where a dimension line ends, extending past the dimension line about 1/16" (5.2.5). - Dimension lines — thin; show size or location, with the dimension figure about halfway between the…

Key Concepts

Units and classification - A solid masonry unit is one whose cross-sectional area in every plane parallel to the bearing surface is 75% or more of its gross cross-sectional area measured in the same plane; cored brick remains "solid" as long as the holes are less than 25% of the cross-sectional area (Modern Masonry, 9th ed., p. 123). - Green bricks are formed but not yet fired; they contain 5% to 30% moisture as they come from the molding or extruding machines (p. 115). - Building brick grades: Grade SW (Severe Weathering) is highly resistant to frost action — foundation courses, retaining walls; Grade MW is for moderate exposure (below-freezing temperatures but not likely permeated with water); Grade NW is backup on interior masonry (p. 116; Clay Masonry Materials, Section 7.5.1).

Key Concepts

Materials - Basic mortar ingredients are Portland cement, hydrated lime, and sand. Cementitious materials include Portland cement (Type I, II, or III), masonry cements, and hydrated lime (Type S) (Masonry Textbook, Ch. 10, Sec. 10.1.1). - Hydrated lime comes in Types S and N. Only Type S is recommended for masonry mortar because unhydrated oxides and plasticity are controlled, which improves bond to the units. These properties are not controlled in Type N (Modern Masonry 9th ed., Ch. 10, p. 187; Masonry Textbook, Sec. 10.1.1). - ASTM standards for mortar materials: C150 Portland cement (Types I, II, III); C207 hydrated lime; C5 quicklime; C91 masonry cement; C144 aggregate (sand) (Masonry Textbook, Sec. 10.1.2 / Figure 10-1). Grout aggregates are covered by ASTM C404; grout itself by ASTM C476. - Because compressive strength of masonry mortar is less important than bond strength, workability, and water retentivity, those latter properties should be given principal consideration in selection (Sec. 10.1).

Key Concepts

Wall ties — purpose and function Wall ties are strips of metal or metal wire used to tie masonry wythes together or to tie masonry veneer to a concrete frame or wood frame wall. They perform three functions — transfer lateral loads, provide a connection, and permit or restrain movement between different materials in a wall. Metal wall ties can also serve as horizontal structural reinforcement. (Section 11.1, Metal Ties or Wires)

Structural bonding with metal ties or wires is widely used in three types of construction: masonry veneer to frame, solid masonry, and cavity wall. (Section 11.1)

The four basic types of metal wall ties are unit ties, continuous horizontal joint reinforcement, adjustable ties, and re-anchoring systems. (Section 11.1.1, Types of Ties)

Topic weight: 1 question (3% of exam). Subtopic: General.

Key Concepts

Three categories of stone (by process of formation). Stone is divided into three categories based on the process of formation: igneous (volcanic), sedimentary, and metamorphic (Modern Masonry, 9th ed., Chapter 9, Page 174). The categories are often related — a given sample of rock may have resulted from more than one formation process. Mineral variation affects strength, color, texture, and durability, especially in marble, limestone, and sandstone.

Igneous stone is classified by texture, mineral content, and origin, and all of it comes from magma (a molten mixture of minerals). When composed primarily of light minerals (quartz and potash feldspar), igneous stone is called acidic — light in color and weight. Igneous stone with a greater degree of ferro-magnesian minerals is called basic — darker and heavier (Masonry Textbook, Chapter 9, Section 9.1.1). Two popular types: granite (hard, takes a good polish, best known of the deeper igneous stone) and traprock (the quarryman's term for diabase, basalt, or gabbro; contains iron minerals that create…

Subtopic: General

Key Concepts

Trowels — pattern determines use (Modern Masonry, 9th ed., Ch. 3, Sec. 3.1.1 Trowels) - Philadelphia pattern trowels allow more mortar to be placed on the blade, so they are best suited for applying mortar to block. - London pattern trowels have the standard blade type for laying brick. - Wide London pattern trowels have a rounded heel, which places the mortar farther forward on the blade compared to the Philadelphia pattern trowel; a Wide London pattern trowel can be used for laying brick or block. - Trowel anatomy: the narrow end of the blade is the "point," the wide end nearest the handle is the "heel," and the blade connects to the handle by the shank. - Trowels are available in lengths from about 3" to 13". - Wood handles are most common and usually have a ferrule (metal band) around the shank end; the ferrule adds strength and prevents the handle from splitting.

Arkansas Masonry – Commercial Exam | 2 questions (7%)

The SOURCE treats cleaning and restoration as part of workmanship: preventing the staining and deterioration that would otherwise have to be repaired, and removing mortar correctly during and after laying. Learn the causes of efflorescence and spalling, the cavity-cleaning techniques, and the correct timing and tools for finishing and cleaning joints.

Key Concepts

Causes of deterioration - Leaky walls result from partially filled mortar joints, which contribute to spalling — "the deterioration or flaking off of the brick." Spalling is due to freezing and thawing when excessive moisture is present. Voids in the mortar can be the first location where moisture starts to enter the masonry wall surface. (Modern Masonry, Ch. 12, "Workmanship," Page 243) - All mortar joints intended to receive mortar must be completely filled as the units are laid. (Page 243) - If excessive moisture accumulates behind the brick, as the moisture migrates through the brick it will accumulate on the exterior surface, creating efflorescence stains. A more damaging occurrence is moisture…

Key Concepts

Safety training and education — 29 CFR §1926.21(b) - The employer shall instruct each employee in the recognition and avoidance of unsafe conditions and the regulations applicable to his work environment (§1926.21(b)(2)). - Employees required to handle or use poisons, caustics, and other harmful substances shall be instructed regarding the safe handling and use, and be made aware of the potential hazards, personal hygiene, and personal protective measures required (§1926.21(b)(3)). - Where harmful plants or animals are present, exposed employees shall be instructed on potential hazards, how to avoid injury, and first aid procedures (§1926.21(b)(4)). - Employees handling flammable liquids, gases, or toxic materials shall be instructed in safe handling and use (§1926.21(b)(5)).

Employee emergency action plans — §1926.35 - The plan shall be in writing, except as provided in the last sentence of paragraph (e)(3) (§1926.35(a)). - The written plan shall be kept at the workplace and made available for employee review. **For those employers with 10 or fewer employees the plan may be communicated orally to employees and the employer…