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Building Code Requirements for Structural Concrete provides minimum requirements for the design and construction of structural concrete members of any structure erected under the requirements of a general building code that incorporates it.

ACI 23

ACI 318 Building Code Requirements for Structural Concrete provide minimum requirements for the design and construction of structural concrete members of any structure erected under the requirements of a general building code that incorporates it.

American Concrete Institute.

is an authoritative reference in the US for steel building structure design published by AISC.

AISC 360

is a technical institute and trade association for the use of structural steel in the construction industry. Their mission is to make structural steel the material of choice for new structures.

American Institute of Steel Construction

is the local counterpart of ACI 318 and governing code in the Philippines

National Structural Code of the Philippines (NSCP)

NSCP

National Structural Code of the Philippines

The same with ACI 318, it provides minimum requirements for the design and construction of structural concrete members of any structure erected under the requirements of a general building code that incorporates it.

Association of the Structural Engineers of the Philippines (ASEP)

is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services

American Society for Testing and Materials (ASTM)

is a standards setting body which publishes specifications, test protocols and guidelines which are used in highway design and construction throughout the United States.

American Association of State Highway and Transportation Officials (AASHTO)

Despite its name, the association represents not only highways but air, rail, water, and public transportation as well.

American Association of State Highway and Transportation Officials

Bureau of Product Standards (BPS)

These standards not only protect the consumers but also facilitate trade in the global market.

International Code Council (ICC)

Nonprofit, limited liability company that does technical evaluations of building products, components, methods, and materials.

CMT

Construction Material Testing

Construction Material Testing

These laboratories fulfill the requirements of ASTM Engineering Standards.

widely used in domestic, commercial, recreational, rural and educational construction.

Concrete

Concrete is made by mixing:

cement, water, coarse and fine aggregates, admixtures

The aim is to mix these materials in measured amounts to make concrete that is easy to:

Transport, Place, Compact, Finish

The cement powder, when mixed with water, form a

cement paste

-Water

-Cement

-Sand

Mortar

-Water

-Cement

-Aggregates

-Admixtures

Concrete

-Water

-Cement

Cement Paste

Cement should\_____off the ground in a well-aired, clean, dry place

be stored

Main difference of the cement types is its \_______ which affects the properties of the cement.

chemical composition

hydraulic cements, meaning they react and harden chemically with the addition of water.

Portland cements

contains limestone, clay, cement rock, and iron ore

Cement

- MIXING

- INDUCTION

- ACCELERATION

- DECCELERATION

- DIFFUSION LIMITED

cement

water divide by cement

Water Cement Ratio

remove rust in steel

steel brush,

turco,

red oxide

crushed rock, gravel or screenings.

Coarse aggregates

natural sand or crushed stone with particles smaller than 3/8

Fine Aggregates

Aggregates should be:

Strong and Hard

Durable

Chemically inactive

Clean

Graded

If the aggregates are very wet

use less water in the mix

make concrete harder to place, work and compact, but can make concrete stronger

Angular Aggregates

combine with water

hydration

mixed with the cement powder to form a paste which holds the aggregates together like glue.

water

Water must be

clean, fresh and free from any dirt, unwanted chemicals or rubbish that may affect concrete.

Materials added to alter the properties of concrete, such as air entrainment, set accelerators, set retarders, and water reducers.

Chemical Admixtures

Mineral admixtures include fly ash, hydrated lime, silica fume and ground blast furnace slag

Mineral Admixtures

add microscopic air bubbles to the concrete, enhancing its resistance to freeze/thaw cycles and makes the concrete easier to finish.

Air entraining admixtures

speed the set - time of the mixture, enabling finishing operations to begin sooner, useful during cold weather pours.

Set accelerators / acceleration plasticizers

have the opposite effect, slowing the set and enabling delivery to distant sites and finishing during hot weather.

Set retarders / retarding plasticizers

are used to reduce the amount of water required to produce a given slump. They also provide a ball bearing effect, making the concrete easier to finish, and produce better cement hydration. By reducing the amount of water required, cement amounts can be reduced because concrete strength is directly related to the water/cement ratio.

Water reducers

Mineral additives are also known as

Pozzolanic

Workability

Cohesiveness

Strength

Durability

four main properties of concrete

When the concrete is first mixed it is like 'bread dough'. It is soft and can be worked or molded into different shapes

Plastic State

Concrete then begins to stiffen. The stiffening of concrete, when it is no longer soft

Setting State

After concrete has set it begins to gain strength and harden.

Hardening State

The properties of hardened concrete are

strength and durability

Method of keeping concrete at a suitable temperature and moisture level over an extended period of time so that hydration can provide the appropriate concrete qualities

Curing

can be used to measure the workability of concrete

slump test

Well-graded, smooth, \_____ improve the workability of a mix.

aggregates

WORKABLE MIX:

cement paste, \________, admixtures

well graded aggregates

Strength and durability are affected by the \_____ of the concrete

density

Denser concrete is more

watertight

Strength of concrete in the hardened state is usually measured by the

compressive strength

is removing the air from concrete. Proper compaction results in concrete with an increased density which is stronger and more durable

Compaction

is keeping concrete damp for a period, to allow it to reach maximum strength. Longer curing will give more durable concrete.

Curing

cause concrete to have a higher early strength

Weather

Too much water and not enough cement means concrete will be weaker and less durable

Water to Cement Ratio

The lower the ratio, the stronger the concrete.

TRUE

how well concrete holds together when plastic without losing its homogeneity.

Cohesiveness

means that there is a range of size of aggregates, from large rocks to small sands.

Graded Aggregate

give a more cohesive mix, too much coarse aggregate gives a boney mix

Well-graded aggregates

A mix that has too much water will not be cohesive and may separate and bleed.

Water Content

Difference in color across the surface of concrete. May appear as patches of light and dark.

Color Variation

A network of fine cracks across the surface of concrete.

Crazing

A fine powder on the concrete surface which comes off on your fingers.

Dusting

The surface has bits washed away or many small dents

Rain Damage

When the slab edges and joints chip or break leaving an elongated cavity

Spalling

white crystalline deposit sometimes found on the surface of concrete soon after it is finished.

Efflorescence

When too much coarse aggregate appears on the surface.

Honeycombing

are hollow, low profile bumps on the concrete surface filled with either air or bleed water

Blistering

Random cracking in concrete is not desirable, it can make your concrete look ugly and lead to structural weakness of the concrete.

Cracking in Concrete

Cracks that happen before concrete hardens, while it is still workable.

Pre-setting Cracks

Cracks which happen after concrete hardens.

Hardened Crack

They form soon after concrete is placed, while it is still plastic. They get bigger as concrete dries and shrinks and tend to follow the lines of reinforcement.

Plastic Settlement cracks

On very hot days or in low humidity and moderate winds. Cracking is more common in summer but may occur during winter

Plastic Shrinkage Cracks

is not strong enough it may bend or bulge.\_____may happen at any time during placement and compaction

Formwork Movement

Applying cold water, as curing, over concrete on a hot day can result in cracks from the sudden contraction.

Thermal Shock

may be caused by drying shrinkage, movement or settling of the ground, or placing higher loads on the concrete than it was designed to carry.

Hardened Crack