Construction Materials Flashcards
What’s a Skill saw
handheld saw used for perpendicular precision cutting
What’s an impact drill
drill used for hammering screws through harder wood
what is a minter saw
a saw that can be used for precision cutting of all angles
The ease of mixing, transportation, placement and finishing concrete material without segregation is called
workability
Typically, you can expect to have approximately ________ minutes after ready-mix concrete is mixed before placing before it starts to become unusable.
90 minutes
To avoid segregation of concrete material, you want to have a really wet mixture.
true
A deficiency in fine aggregates for a concrete mix can result in a mix that is difficult to finish.
true
A deficiency in fine aggregates for a concrete mix can result in a mix that is difficult to finish.
false
A concrete paste typically comprises of_________
water, Portland cement, sand, gravel
The quality of concrete isn’t dependent on the quality of the concrete paste.
true
a non-air-entrained concrete with a 0.5 water:cement ratio should expect to have approximately what level of compressive strength?
4500 psi
Air entraining, water-reducing and retarders can all be considered concrete
admixtures
Typically, you would usually find concrete specifications (not for curbs etc.) in CSI MasterFormat 2016’s division ____
3
Types of “Needs?”
Infrastructure, Heavy Civil, Institutional, Commercial Construction, Residential
Subcontractors
Mechanical – Heating, Ventilation, Air Conditioning
(HVAC), Electrical, Plumbing, Landscape, Drywall, Structural, Windows & Doors, Signage
Concrete mix is designed to:
Achieve design requirements (strength, permeability, etc.), Easy mix and transport, Workability (No segregation, easy filling of formwork)
Characteristics of cement,
Proportions of the raw materials used, Fineness of the grinding of the clinker (used to produce
cement)
Quality of concrete is highly dependent on the
quality of paste
Amount of water used in relation to the amount of cement
Fresh Concrete Needs
To be easily mixed and transported, To be uniform throughout a given batch and between
batches, to fill completely the forms for which it was designed, The ability to be compacted fully without an excessive
amount of energy applied, Must not segregate during placing and consolidation, Capable of being finished properly
Short Term Criteria for Concrete
Workability - ease of mixing, transportation, placement and finishing concrete material without segregation, Timing – how long to place ready-mix concrete?, 90 minutes after mixing of material
Long Term Criteria for Concrete
▪ Strength, Durability, Volume Stability
Concrete should be
workable, not segregate, or bleed excessively
Slump test
a measure of concrete workability
Determined by
w : c ratio, aggregate type & size, admixtures
As outside temperature increases
workability decreases
Workability is measured by
slump test
Separation of particles which are present in concrete.
Segregation due to separation of aggregates, Segregation due to separation of paste
Tips
Avoid too wet or dry of a mixture, Avoid placing from too high of a height, Use concrete vibrating machine when
feasible, Ensure formwork is tight and secure, Consider placing in multiple places in a wall form
Increasing the water content may
increase the ability of the concrete to flow and compact
Increasing water may also lead to:
Segregation, Bleeding, Decreased strength
Weight of water
cement
per unit volume (cy)
Advantages of reducing
w:c ratio:
Increased compressive & flexure
strength, Lower permeability, Increased resistance to
weathering, Better bonding, Less volume change from
wetting and drying, Reduce shrinkage cracking
Fine
natural or manufactured sands, <3/8”
Coarse
Gravel / crushed stones , <6”, Typical 3/4”-1 1/2”
Types
Course aggregate (gravel, crushed stone): Those retained in No. 4 sieve (4 openings per linear inch), Fine aggregate (natural or manufactured sand): those that can
pass No.4 sieve.
The maximum size of aggregate is governed by
ACI code
Deficiency in fine aggregate leads to:
Harsh mix, Prone to segregation, Difficult to finish
Influence of Aggregate
Gradation, Shape and Texture, Porosity
Influence of Aggregates pt.2
Bottom Line, Well-graded aggregate produces concrete that is easier to
place, Well-graded aggregate produce stronger concrete that is
more economical
Admixtures
Ingredients other than water, cement, and aggregate to
control specific characteristics of the concrete. They modify the property of concrete to make it suitable for
the work at hand or for economy, Air entraining, water-reducing and retarders all improve
workability
Key to mix design is to proportion all the concrete
components to provide:
Workability, Strength, Durability
Quality of cement
Cement to water ratio in the mixture, Strength and cleanliness of aggregate, Adhesion between cement paste and aggregate, Adequate mixing of ingredients, Proper placing, finishing and compaction of fresh
concrete, Curing at temperature not below 50 degrees
Wide variety
sizes and colors
Weight
Lightweight (~28lbs/less) lighter
aggregates vs. Normal/Heavy (~34-35 lbs)
Modular system
Pieces or parts, Larger unit than
brick, Dimensions related
to modular brick
Hollow Concrete Block
Most common CMU
▪ Below is a stretcher block
▪ Sizes
▪ Width 4, 6, 8, 10, 12 inch (nominal - less 3/8”)
▪ 8” most common
▪ Height - 7 5/8”; length 15 5/8”
▪Height - 8” = 3 courses of brick
Hollow Concrete Block Placement
More economical to lay than brick, Larger size - less to lay for same area, Lay similar to brick
Hollow Concrete Block Strength(s)
What is expected? 3,000 psi
Hollow Concrete Block Reinforcing
Cores - conducive for deformed rebar, Increases load bearing, Helps resist cracking
Uses and Finishes
Back-up “wythe” for brick or stone, Accepts plaster, stucco, tile, Exposed - coated
Moisture Penetration
Needs coating, Bituminous Membrane, Latex Filler
Best Value
Any selection process by which proposals contain both price and qualitative components and the award is based upon a combination of price and qualitative considerations.
Closed Bid
Used with private projects and is not open to the public. Bidding is by invitation only, via an invitation for bids, to a selected list of contractors
Price Proposal
The part of a design-build proposal that stipulates the price at which the design-builder will provide the design and construction services necessary to complete the project.
Weighted Criteria
An evaluation method used in best-value selection in which maximum point values are assessed for qualitative and price components of a proposal. Contract award is based upon the highest total points earned.
Name the two primary selection criteria categories considered when using the best-value method.
The two primary selection categories are price (quantitative) and technical aspects (qualitative).
Construction Management
Planning, scheduling, evaluation and controlling of construction tasks and activities to accomplish specific objectives outlined in the contract documents
Fast Tracking
A practice used to speed up the construction process by overlapping the design and construction phases. This method is often applied in design-build or construction management project delivery
Name the four primary project values to be managed, monitored, and controlled.
Time, Safety, Quality, Cost
Base Isolators
shock absorbers placed in a building foundation to allow movement without causing damage
Brownfield Sites
reclaiming and building on sites that have been previously abandoned or underused because of historic environmental contamination
Constructability Review
reviewing the plans to determine if it is feasible to build
Cofferdam
temporary watertight structure that allows for construction to occur in a water free environment
Which CSI division?
Division 6
Engineered Wood Products
Attempt to improve the basic properties of lumber
▪ strength
▪ appearance
▪ dimensional stability (retaining its dimensions)
▪ cost
▪ Uses fast-growing, low-density wood species
▪ Typically for:
▪ Sheathing
▪ Main Structural Members
Potential disadvantages
out-gassing from formaldehydes
▪ deterioration under certain conditions
▪ FRT (fire resistant treated) plywood
▪ appearance
Sheathing
A covering for framing
▪ Can assist with framing bracing/support
Why Panelize?
More “controlled” product
▪ Efficient use of forest products
▪ Increase labor productivity
Types
Plywood panels
▪ Composite panels
▪ Non-veneered panels
Veneered Panels - Plywood
The Original Engineered Wood Product”
▪ Thin layers of veneer (thin slices of wood)
▪ Bonded under heat and pressure w/ strong adhesives
▪ Odd number of veneers
▪ Alternating direction of veneers
▪ Face veneers parallel
▪ Size: 4’x8’ panels
▪ Thickness: ¼” to 1”
Veneered Panel Grades
Based on smoothness and integrity of veneers
▪ Veneer quality on the face is graded with a letter
designation
▪ A – No knots
▪ B – Any knots replaced with plugs
▪ C – Knots over ¾” plugged
▪ D – Knots over ¾” present
Exterior
made with high quality
veneers & waterproof glue; for siding
or other continuous exposure to H2O
Exposure 2
waterproof glue but
lower quality veneers; for short term
exposure to H2O; for subfloors and
sheathing
Exposure 2
non-waterproof glue; for
use in protected environments &
minimum wetting; for cabinets, etc.
