MATERIALS - MASONRY Flashcards
composition of MORTAR
Mixture of cement, lime, sand and water (usually portland cement)
mortar type M
2500 psi - heavy loads, BELOW GRADE, retaining AND FOUNDATION WALLS
mortar type S
1800 psi - MEDIUM HIGH STRENGTH, at and below grade, WHERE BOND AND LATERAL Strength IS MORE IMPORTANT THEN COMPRESSIVE STR
mortar type N
750 psi - MEDIUM STENGHTH , common, exterior above grade
mortar type O
350 psi - non-loadbearing, historic structures
mortar type K
VERY LOW STRENGTH , INTERIOR, NON-LOADBEARING
DIFFERNCE Grout and mortar
Grout is used to fill the gaps between tiles. Mortar is the adhesive that attaches tiles to the floors and walls. Mortar often contains hydrated lime; grout usually contains little if any hydrated lime.
Face brick TYPE FBX
Minimum Variance In Size And Color
Face brick TYPE FBS
wider color range permitted
Face brick TYPE FBA
non-uniformity
Brick Grade SW
exposure to Severe weathering and ground
Brick Grade MW
exposure to Moderate weathering
Brick Grade NW
exposure to Negligible weathering - interior
CMU GRADE N
load bearing above and below grade
CMU GRADE S
load bearing, limited to above grade
Igneous rocks
from solidification of molten rock. Granite
granite is strong and can be used underground
Sedimentary rocks
consists of consolidated products of rock disintegration, seashells, and various clays and silts. Sandstone Lime stone
Limestone is porous, does poorly in polluted air
Metamorphic rocks
formed of either Igneous or sedimentary rocks that have been altered by pressure or intrusion of molten rock or other liquids over a long period of time. Marble Slate
BRICK SIZE NOMINAL AND ACTUAL`
NOMINAL: 4 X 2.5 X 8
ACTUAL: 3-5/8 X 2-1/4 X 7-5/8 WITH 3/8 MORTAR JOINT 3 COURSES WITH MORATR COME UP TO 8”
Paving Brick - SX Grade
Severe Xposure Resistant to frost/freeze and thaw, used for paving, high install cost
Paving Brick - MX Grade
Moderate Xposure Not recommended for saturated applications, Only use for paving in dry or well draining areas
Paving Brick - NX Grade
No Xposure Not suitable for paving purposes
HOW LONG CAN MORTAR BE MIXED BEFORE HAVING TO DISCARD IT?
If mortar is mixed less than 90 minutes prior to its stiffening it has only dried and a mason can safely retemper it with water to make it workable again (note, this is not the case with concrete!)
Mortar older than 2 1/2 hours must be discarded because it has begun to hydrate and can’t be retempered without reducing its final strength
Stretcher
• Stretcher: a brick laid with its face parallel to the wall and its long dimensions horizontal
Header
Header: a brick laid to bond two wythes together
Solider
Solider: brick laid on its end with its face (long skinny side) parallel to the wall
Sailor
Sailor: brick laid on its side with its end parallel to the wall
• Running bond
• Running bond: entirely of stretchers
• English Bond:
• English Bond: alternates course of headers and stretchers
• Common Bond
• Common Bond: header course every sixth course, head joints are aligned
• Flemish Bond
• Flemish Bond: alternates headers and stretchers in each course
Strap anchors:
Strap anchors: galvanized steel attachment
Dovetail anchors:
Dovetail anchors: splayed tenon that fits into the recess of a corresponding mortise
Cramp anchors:
Cramp anchors: used under coping stones at vertical joints to tie 2 stones together
Pin anchor:
Pin anchor: anchor placed into a drilled hole and a pin is hammered in
Threaded dowel:
Threaded dowel: used at vertical/horizontal joints between panels to align and maintain distance between panel and backup structure
External Flashings:
External Flashings: prevent moisture from penetrating into the masonry wall
where the wall intersects the roof
• At the intersection of a flat roof and wall parapet it’s constructed in tow overlappin parts, a base flashing and a counterflahsing or cap flashing
- Allows for some movement between the wall and roof components
- Base flashing should be turned up for at least 8” tall
Internal (Concealed) Flashings:
Internal (Concealed) Flashings: catch water that has penetrated a masonry wall and drain it through weep holes to the outdoors
Required at every location where the cavity is interrupted (e.g.: window heads, door heads, window sills, shelf angles, spandrel beams)
Installed by masons that construct the wall
Should be turned up 6” - 9” at the interior face of the wall
Should penetrate at least 2” into the interior wythe
Can be made of sheet metal, plastic, elastomeric compounds, or composite material.
• Sheet metal is the most durable and most expensive
• Copper and stainless steel is best
• Galvanized steel eventually rusts and disintegrates
• Aluminum and lead are unsuitable because they react chemically with mortar
• Plastics re the least expensive, some are good, some are bad.
Increasing mortar flow
Increased mortar flow also increases mortar’s bond strength because the wetter the mortar the more it can fill in the pores.
Increasing portland cement in mixture?
Increasing portland cement in mixture, increases the compressive strength of the mortar. Decreasing Portland cement therefore decreases the compressive strength but doesn’t necessarily mean an increase in the flow or water content.
