Introduction ARCHITECTURAL STUCTURES

Question 1

are categorized as either
reinforced concrete (RC) or prestressed concrete (PSC)

Answer 1

Concrete structural construction components

Question 2

NSCP

Answer 2

National Structural Code of the Philippines

Question 3

is made up of two materials: 1) concrete which is strong in
compression but very weak in tension and 2) steel which is strong in both tension
and compression

Answer 3

Reinforced concrete

Question 4

s composed of three materials, namely: cement, fine aggregates and
coarse aggregates.

Answer 4

Concrete

Question 5

Attains high strength in 7 days, 3 days or even 1
day

Answer 5

Rapid Hardening Cement

Question 6

Used primarily in situations where the work needs to
be completed in a very short period of time (e.g. concreting under water)

Answer 6

Quick Setting Concrete

Question 7

Used for massive construction

Answer 7

Low Heat Cement

Question 8

Used as a cheaper alternative

Answer 8

Blast Furnace Slag Cement

Question 9

Ideal for concreting of marine structures and other
concreting works under water

Answer 9

Pozzolanic Cement

Question 10

is an important component for mortar or concrete.

Answer 10

Water

Question 11

When the water is
mixed in _____, it reacts with cement and forms a binding paste which fills small
voids in the sand

Answer 11

mortar

Question 12

Only ______ can be
used in the concrete mix since impurities in dirty water generally has an adverse
effect on the concrete strength

Answer 12

clean water

Question 13

Aggregates, which account for _____________ of
the total volume of concrete

Answer 13

60 to 75 percent

Question 14

is defined as material that will pass a No. 4 sieve and will, for the
most part. be retained on a No. 200 sieve

Answer 14

Fine aggregate

Question 15

is a material that will pass the 3-inch screen and will be
retained on the No. 4 sieve

Answer 15

Coarse aggregate

Question 16

Two characteristics of aggregates have an important influence on proportioning
concrete mixtures because they affect the workability of the fresh concrete. They
are:

Answer 16

1. Grading
2. Nature of particles

Question 17

(particle size and distribution)

Answer 17

Grading

Question 18

(shape, porosity, surface texture

Answer 18

Nature of particles

Question 19

provide enhanced concrete quality, improved durability and deliver
cost-benefits to both the producer and the user.

Answer 19

Admixtures

Question 20

Commonly Used Concrete Admixtures

Answer 20

1. Set Retarding
2. Air-Entrainment
3. Water-Reducing
4. Accelerating
5. Shrinkage Reducing
6. Super Plasticizers
7. Corrosion-inhibiting

Question 21

These are used to delay the chemical reaction that takes place when the concrete
starts the setting process. This type of concrete admixture is commonly used to
reduce the effect of high temperatures that could produce a faster initial setting of
concrete. Also, this is a requisite for transporting ready-mix concrete (RMC) to delay
the setting while the mix is in transit

Answer 21

Set Retarding

Question 22

concrete can increase the freeze-thaw durability of concrete. This type
of admixture produces a more workable concrete than non-entrained concrete
while reducing bleeding and segregation of fresh concrete.

Answer 22

Air-Entrainment

Question 23

are chemical products that when added to concrete
can create a desired slump at a lower water cement ratio than what is normally
designed.

Answer 23

Water-Reducing

Question 24

used to increase the rate of concrete streng
development, or to reduce concrete setting time. Calcium chloride could i named
as the most common accelerator component; however, it could promor corrosion
activity of steel reinforcement

Answer 24

Accelerator concrete admixtures

Accelerating

Question 25

concrete admixture is added to concrete during initial mixing. This type of admixture could reduce early and long-term drying shrinkage

Answer 25

Shrinkage Reducing

Question 26

to produce flowing concrete will very high slump in the range of 7-9 inches to be used in heavily reinforce structures and in placements where adequate consolidation by vibration canne be readily achieved.

Answer 26

Super Plasticizers

Question 27

all into the specialty admixture category and are used to slow corrosion of reinforcing steel in concrete

Answer 27

Corrosion-inhibiting

Question 28

has relatively high compressive strength, but significantly low tensile strength, and as such is usually reinforced with materials that are strong in tension.

Answer 28

Concrete

Question 29

The density of concrete varies, but is around

Answer 29

2,320 kilograms per cubic meter (22.8 kN/cu.m)

Question 30

The unit weight of reinforced concrete used for load calculations can be conservatively taken as

Answer 30

24 kN/cu.m

Question 31

the NSCP Code formula for concrete modulus of elasticity is

Answer 31

Ec = 4700 √ fc'

Question 32

According to the NSCP 2015 (Art. 422.2.2.1), the maximum usable concrete strain is take as

Answer 32

0.003

Question 33

Traditionally, the concrete grade commonly used has a strength of

Answer 33

21 MPa (3,000 psi)

Question 34

The tensile strength of concrete is defined as the ___________

Answer 34

modulus of rupture, f.

Question 35

Types of Concrete

Answer 35

1. Lightweight Concrete 2. High Density Concrete 3. Mass Concrete 4. Ready-mix Concrete 5. Shotcrete

Question 36

One of the main advantages of normal weight concrete is the heavy self- weight of concrete. Density of normal concrete is of the order of 2200 to 2600 kg/m^3. This self-weight will make it to some extent an uneconomical structural material.

Answer 36

Lightweight Concrete

Question 37

They are mainly used in the construction of radiation shields (medical or nuclear). -used for ballasting for pipelines and similar structures

Answer 37

High Density Concrete

Question 38

sometimes preferred over on-site concrete mixing because of the precision of the mixture and reduced worksite confusion.

Answer 38

Ready-mix Concrete

Question 39

It is defined as a mortar conveyed through a hose and pneumatically projected. high velocity on to a surface. There are mainly two different methods nans wet mix and dry mix process.

Answer 39

Shotcrete

Question 40

also known as reinforcing steel, is a steel bar or mesh of steel wires used primarily as a tension device in reinforced concrete and reinforced masonry structures to strengthen and hold the concrete in tension. In some instances, rebars are also used as compression reinforcements.

Answer 40

Rebar (short for reinforcing bar)

Question 41

Basic Load Combinations (From NSCP 2015, Art. 203.3.1)

Answer 41

1.4 (D + F) 1.2 (D + F + T) + 1.6(L + H) + 0.5 (Lr or R) 1.2D + 1.6(Lr, or R) + (f1L or 0.5W) 1.2D + 1.0W + f1L + 0.5(Lr or R) 1.2D ±1.0E + f1L 0.9D + 1.0W + 1.6H 0.9D ±1.0E + 1.6H

Answer 42

1.2D + 1.6L 1.2D + f1L + 1.0W