Consmat

concrete

most widely used construction material

cement

sand

gravel

water

components of concrete

cement

fine, soft powder used as a binder because it hardens after contact with water

sand

Or fine aggregates, natural sand, or crushed stone well-graded

gravel

Or coarse aggregates, crushed stone, or blast furnace slags

water

Clean, potable, and free from harmful substances

admixture

or additive as required by situations to modify its properties immediately before, or after mixing

AAA

concrete grade used for Pre-stressed and post-tensioned

AA

concrete grade used for Underwater retaining wall, shear wall, and core elevator walls

A

concrete grade used for Footings, pier, column, girders, beams, joists, and slabs

B

concrete grade used for Slabs on fill and non-load bearing wall or 4" CHB

C

concrete grade used for Concrete plant boxes and parapet walls

D

concrete grade used for Plant boxes, footpaths, walkway, and lean concrete

low

moderate

high- strength concrete

general categories of concrete

< 20 MPa (<3,000 psi)

low-strength concrete strength

20 - 40 MPa (3,000 - 6,000 psi)

moderate-strength concrete strength

>40 MPa (>6,000 psi)

high-strength concrete strength

light

normal weight

heavy

categories of concrete by weight

(AAA - D)

Cement : 1

Sand : 1 + 0.5 (per grade)

Gravel : 2 + 1 (per grade)

concrete grade ratio

Class A

common concrete class used in sites

water cement ratio

controls the strength, durability and water tightness of hardened concrete

inversely

the compressive strength of concrete is _____ proportional to the ratio of water to cement

weaken

Too much water will _____ concrete after curing

6 gallons

The average water-cement ratio is ____ per 40 kg of cement bag

bleeding

emergence of excess mixing water to the surface of newly placed concrete cause of settlement of solids within the mass

laitance

milky deposit containing cement and fine aggregate on the surface of new concrete combined with bleeding, overworking of mix of improper finishing

creep

Long duration stress produces stress over time and consequently causes permanent deformation

fire resistant / incombustible

Concrete is _____ and somewhat insulative, but long exposure to fire can be damaging

moisture by proper curing

To avoid shrinkage in concrete, maintain ____

hardness

Relative to durability and appearance, accomplished thru troweled or floated finish to draw more paste to the surface

porosity

Sizes of pores left during hydration process or created by excessive evaporation and shrinkage cracks affecting the water-tightness of concrete.

compaction techniques

porosity is affected by

durability

Concrete ____ requirements are specified on most major bridge and pavements projects.

Rapid Chloride Permeability Test (RCPT)

durability reqs are typically based on

Rapid Chloride Permeability Test (RCPT)

This is a surrogate procedure which measures flow of electrical current.

workability

Refers to how easily fresh concrete can be placed without loss of homogeneity

rheological properties

Workability of fresh concrete depends on its ____. This is defined by two characteristics of the concrete, i.e. yield stress and plastic viscosity

cement + sand + water

composition of mortar

mortar

binds bricks and stones to provide strength, forms a solid mass that resists loads, protects masonry from weather, holds aggregates together in concrete, and is used for plastering, painting, and filling joints through grouting.

cement mortar

is a mix of cement, sand, and water (1:2-8) used within one hour and applied in high-strength works like load-bearing walls, foundations, and floors.

lime mortar

made by mixing lime, sand, and water; it is weaker and less watertight than cement mortar, should not be used underground due to poor performance in damp conditions, and is mainly used for above-ground construction in exposed areas.

lightweight mortar

made by mixing wood powder, wood sawing or sawdust with cement or lime mortar, generally used as fiber plasters in sound and heat proof construction

fire-resistant mortar

made by mixing aluminous cement, finely crushed fire bricks, and water (1:2) and is commonly used for ovens and fireplaces with fire bricks.

mud mortar

made by mixing clean clayey soil with water; it is the cheapest but weakest mortar and is used for brickwork and wall plastering in ordinary and rural buildings.

cement

popular building material with adhesive and cohesive properties that bind fine and coarse aggregates together, fill voids between particles, and form a compact, solid mass.

cement paste

a mixture of cement and water

cement mortar

a mixture of cement, sand & water to form a paste

cement concrete

a composite product which is obtained by mixing cement, water, inert matrix of sand and gravel or crushed stone

pozzolan

portland

2 major kinds of cement

pozzolan cement

The ancient Romans discovered that adding volcanic earths to lime produced a hydraulic material that could harden under water

portland cement

It is a hydraulic cement composed primarily of hydraulic calcium silicates. Hydraulic cements set and harden by reacting chemically with water and maintain their stability underwater.

dehydration

An important principle to remember about the cement making process is the ____ (draining out) of the materials by using intense heat.

Type I and Type IA

type of portland cement: Suitable for all general uses such as pavement, sidewalks, buildings, bridges, tanks, water pipes, etc

air-entraining agent

"A" suffix in types of portland cement means an ____ is added in the cement during its manufacturing process.

Type II and Type IIA

Used when the acid or sulphate content of the groundwater or soil is higher than the normal • It generates heat of hydration at a slower rate than Type I • Used in large piers,

heat of hydration

refers to the amount of heat released when cement reacts with water during hydration process

slower heat of hydration

means concrete generate heat at a slower rate

Type III & IIIA

High early strength, high heat

Fast form removal & early service

Good for cold weather

Type IV

Low heat of hydration

Used in massive structures (e.g., large dams)

Type V

Sulphate/acid resistant

Used in high-sulphate soils, groundwater, or coal mine drainage

Blaine Air Permeability Test or the 45 microns

fineness of cement is measured by

soundness

Refers to the ability of a hardened paste to retain its volume after setting

consistency

Refers to the relative mobility of a freshly mixed cement paste or mortar to its ability to flow

ASTM C150

To determine if cement sets according to the time limits specified in

Initial Setting Time of Cement

the time it takes for the cement paste to start losing its plasticity after mixing with water. (Typically around 60 minutes)

Final Setting Time of Cement

the time it takes for the cement paste to completely harden (Typically within 10 hours for Ordinary Portland Cement)

False Set (ASTM C451)

Standard Test Method for Early Stiffening of Hydraulic Cement (Paste Method)

ASTM C39 : cylinder

ASTM C109 : cube

compressive strength test

3.15

The specific gravity of Portland cement is generally about

2.90

Portland blast furnace-slag and Portland-pozzolan cements may have specific gravity of

Pneumatic

____ loading and unloading of the transport vehicle is the most popular means of handling bulk cement

entrapped air

non uniform air distribution due to insufficient compaction

entrained air

uniform air distribution due to intentional creation with air entraining admixtures

entrained air

air void desired in concrete

entrained air

barely visible to the eye • Chemical admixture that increases the air inthe concrete • It improves the concrete's resistance tofreeze-thaw damage.

Rate of hydration or setting time

Workability

Dispersion

Air-entrainment

Concrete Properties Commonly Modified By Admixtures

reinforcing bars

play a major role in controlling cracks on structural concrete that are caused mainly by the application of loads that induce tensile and shearing stresses

grade

commercial length

diameter

Rebars are available in the market in terms of ______ and can be purchase by piece or by mass.

6 (most readily available)

7.5

9

10

12 m

rebars can be bought in

Philippine National Standards

PNS stands for

Unit mass = density of steel x Bar Area

unit mass formula of rebar

7850 kg/m^3

density of steel

Manufacturer / Producing Mill

first mark (uppermost) in rebar grade markings

Bar size ( + W if weldable)

second mark in rebar grade markings

type of steel

third mark in rebar grade markings

steel grade

fourth mark (lowest) in rebar grade markings

Grade 33

Grade for No rib

Grade 40

Grade for 1 rib

Grade 60

Grade for 2 ribs

white

Color for Grade 33

Yellow

Color for Grade 40

Green

Color for Grade 60

forms

used in holding wet concrete and molding them into the shapes of structural members as desired in the plans.

shuttering

type of formwork that supports vertical side structural members, such as reinforced concrete wall, columns, pedestal and footings

centering

supports the undersides of horizontal structural elements such as beams and slabs.

falsework

Temporary support and braces the formwork or other components of structure during construction until it can support itself.

scaffolds

Temporary support to provide platform for workers to access and work at elevated areas

concrete masonry unit (CMU)

also called as concrete block, cementblock and foundation block, is largerectangular block used inconstruction

tinsmithry

the term for the art or trade ofshaping and installing tin and otherlightweight sheets of metal to formroof coverings, rainwater collectorsand conductors, and also metal claddings

ridge roll/ hip

Serve as cover for the joint of two or more adjacent roofing sheets