Arch Materials Test 2-Masonry test questions and answers

1. Extracting Raw Material 2. Forming Processes 3. Drying 4. Firing 5. Packaging and Distribution Name one of the five main processes in the manufacture of clay bricks A. Concave Joint B. Weathered Joint C. Flush Joint D. V Joint E. Struck Joint F. Raked Joint Identify the mortar joints illustrated Concave Joint A good, standard joint that is universally accepted as the best joint for preventing water penetration. Weathered Joint A fair joint. Due to the slope of the mortar, this joint also performs fairly well. However, water can run across the underside of the brick and enter if the mortar is not well adhered. Flush Joint A poor joint. This joint is susceptible to water sitting on the top of the joint if it protrudes slightly from the brick. V Joint A fair joint. This joint is less successful at shedding water due to the point, which can be an entry point for water if not tooled perfectly. Struck Joint A very poor joint. The slope of the joint pulls water into the joint and allows it to sit on the brick, which gives the water more time to penetrate. (interior use only) Raked Joint A very poor joint. The ledge allows water to sit on top of the brick and potentially get sucked into the wall. (interior use only) Masonry ________ includes ALL BRICKS, STONE, BLOCKS, EARTHEN MATERIALS as well as cementious that are laid (stacked with or without mortar). Masonry - Primarily respect compressive forces -Heavy or high weight to strength ratio -Formed to create walls with small openings, arches, and piers -Known for their fire resistance Mortar A combination of cementitious materials (portland cement, lime or masonry cement); aggregate (sand) and water. Mortar Comprises 20% of the wall surface. Grout Materials used to fill voids between reinforced and unreinforced masonry. This material is used to fill voids between tiles and stone flooring as well. -Plastic state -Hardened state Mortar and grout exist under what two states? -Workability -Water Retension: -Intial flow -Flow after suction What are the plastic state properties? Water retention ___________ is the ratio of flow after suction to initial flow, expressed as a percentage. intial flow The ______ is the percent increase in diameter of a mortar sample when it is placed on a flow table and dropped 25 times in 15 seconds. Flow after suction The same procedure is used to determine flow after some of the mortar's mix water has been removed by an applied vacuum, which is meant to simulate the suction of masonry units on water. -Uniform -Cohesive -Consistent What are three characteristics of the workability of mortar? -Spreads easily on brick (not too stiff) -Holds weight of brick (won't slump) -Makes alignment easy (push into place) -Clings to vertical surfaces (not so dry that it falls off) -Easily extrudes from joints without dropping or smearing (won't fall out or stain side of brick) What are some attributes of the workability of mortar to look for on job sites? Water Retension -Role of Lime: Improves Elasticity of Mortar -Measured by the flow of the mortar (similar to slump test in concrete) -moisture level -separating Insure that mortar retains __________ to prevent mortar from __________ from the masonry. -Bond Strength -Durability -Compressive Strength -Volumn Change -Appearence What are the hardened state properties? -Porosity -Air Temperature/Humidity Level -Workmanship -Amount of Water -Type of Cementitious Material -Air Entrainment Bond strength is affected by: True T/F High temperatures can cause mortar to dry too quickly. False High humidity can slow the curing process T/F Low humidity can slow down the curing process True T/F Movement of units after being laid may cause breaking of bond. Lime Adding _________ increases workability and bonding. 12% If the air content of mortar is > ______% bond strength decreases. Durability -Measured by the ability to resist water penetration. -Prevent the cycles of freeze and thawing that will cause mortor to crack. -Spall -Effloresecence -Subeffloresecence -Staining What are four common problems with durability in the hardened state? Spalling ________ is when the surface of mortar of masonry falls off. Efflorecence ________ involves salt crytallizing on the surface. (visually unsightly only) Subefflorecence ________ involves salt crystallizing in the interior which can cause structural damage. Staining _______ occurs during the building process of by lime leaching out of fresh mortar. Compressive strength -Depends primarily on amount of portland cement. -Excess water decreases __________. Volumn change -During curing, mortar may shrink -Properly tooled joints will prevent significant shrinkage. -Atmospheric conditions -Moisture content of masonry -Admixtures -Tooling of joints Mortar color is affected by: -Sand-lime mortar -Portland cement mortar & grouts -Portland cement: lime mortar and grouts -Masonry cement mortars List the types of mortars Sand-lime mortar Pros: -High workability -High water retention -More flexible than portland cement -Slow hardening allows for cracks to close up Cons: - Hardens at a slow, variable rate - Develops low compression strength - Poor durability, especially under freeze thaw conditions (Typically only used in historic restoration projects for accuracy) Portland cement mortar & grout Pros: -Hardens quickly and consistently -Develops high compressive stregnths -Good durability to freeze thaw. Cons: -Worability is poor -Water retention is poor (Used in ceramic veneer only) Portland cement: Lime mortars & grout Combines advantages of lime and portland cement: -Durability -High early strength -Consistent rate of hardening -High compressive strength -Workability -Water retention -Plasticity (Best of both primary ingredients) Masonry cement mortars Pros: -Premixed bags of mortar Cons: -Proprietary mixtures- no industry-wide standard -Properties not assured -Do not use in reinforced masonry or masonry meant to withstand lateral loads -MaSON Acronym for the 4 types of masonry Type M Recipe: 1 part portland cement; ¼ part hydrated lime; 3 parts sand -Properties: - High strength mortar - max 2500 psi - Greater durability - High compressive strength - Used with reinforced masonry SET BELOW GRADE Type S Recipe: 1 part portland cement; 1/2 part hydrated lime; 4 1/2 parts sand -Properties: - Medium strength mortar - 1800 psi - Use when bonding and lateral strength are most needed - Used in both reinforced and unreinforced masonry where maximum flexural strength is required - Used in beds for granite, marble, and slate - USE WHEN WIND VELOCITIES EXCEED 80 MPH Type O Recipe: 1 part portland cement; 2 part hydrated lime; 9 parts sand -Properties: - Low strength mortar - 350 psi - Used only in interiors - Non load bearing walls - DO NOT USE WHERE WALL COULD BE EXPOSED TO FREEZING CONDITIONS Type N Recipe: 1 part portland cement; 1 part hydrated lime; 6 parts sand -Properties: - MOST COMMON MASONRY MORTAR - Used with exposed masonry ABOVE GRADE - Medium compressive and lateral strengths - 750 psi - Used in typical situations of exterior walls, parapets -Anchors -Reinforcing -Ties All masonry walls require: Anchors Connects the masonry unit to a structural wall. Reinforcing Ties masonry units together; tie two wythes. Ties For veneer walls; connects brick veneer to a structural wall. 1. CMU 2. Isulation 3. Air space 4. Brick Veneer 5. Wire reinforcement maximum 3/16" diameter 6.(Molded plastic) seismic clip - Absorption - Compressive strength - Durability - Natural color - Texture - Size variation What are the properties of clay masonry units? Absorbtion Clay Masonry Units - Plastic clays & burning temperature decrease _______. -Suction: intial rate of _______ should not exceed 20 grams/minute. Compressive strength Clay Masonry Units - 1500 to 20,000 PSI - Depends on burning temperatures - Properties of particular clays Durabiliy Clay Masonry Units -Affected by pore size -Burning temperature (higher = stronger) -Weather: if annual rainfall exceeds 20"/YR & experience freezing temperatures -Exposure to salts Natural colors Clay Masonry Units - Can range from the lightest cream to gunmetal black - Depends on the clay's chemical composition, burning temperature, and method of burning - Naturally have a variety of tones and values