MATERIAL ENGINEER – QUIZ 5

What is the minimum compaction requirement for embankment?

95%

The following factors does not affect the strength of concrete

cores drilled from the structure, except.

Thickness of the core

What is the weight of class A riprap stones?

15 kgs. to a maximum of 25 kgs. with at least 50% weighing

20 kgs.

What is the function of emulsifiers in Liquid asphalt?

To enable asphalt and water to mix.

Which of the following is not authorized to test materials for use

in DPWH project?

Any testing laboratory of local government unit

What is not the most commonly accepted measure of hardness of

aggregates?

Petrographic Test

The temperature of a 7m3 bituminous mix delivered at the project

site is 20°C lower than the required compaction temperature require by

the Job-Mix Formula. As Material Engineer of the project, what should

you recommend?

Reject the delivered material.

Which of the following is not a type of volume change of concrete?

Air Contain

A soil compacted dry will reach a certain dry density. If compacted

again with same compacted effort but this time with water in the soil,

the dry density will be higher because:

Air is forced out of the soil.

In concrete pouring, large variations in the concrete cylinder the

results were observed, this shall be remedied by?

All of the above.

What is the significance of the loss on ignition of cement?

It signifies pre-hydration of moisture uptake of cement

while it is shelved.

What test determines the resistance of deformation of a compacted

asphalt concrete mix?

Marshall Stability Test

What is the maximum test requirements for riprap boulders?

Stone size and specific gravity

Consolidation test is usually performed in _____ samples?

Undisturbed

Undefined compressive strength test is usually performed on _____?

Clayey Soils

Under Item 406, Pre-Stressed Concrete Structures of DPWH

Specifications, post-tensioning of the pre-stressing reinforcement

shall not commence until test on concrete cylinders indicate that the

concrete has attained a compressive strength of at least:

28 MPa

The following are generally time in the production of high

strength concrete except:

Bigger size aggregates are preferred as more voids are

available for cement bonding.

Portland Cement is also called because:

It resembled cement obtained by grinding natural rocks

found in the Isle of Portland.

The purpose of capping concrete cylinders prior to testing

compression is to:

Provide smooth, flat ends that are perpendicular to the

axis of the sample.

It is the class of concrete used for bedding and after each layer

of stone in rubble concrete?

Class B

The amounts of material passing No. 50 and No. 100 sieves are

important to concrete aggregates because:

All of the above.

A transit mixer for road construction was found to have 6” slump

of fresh concrete instead of the required 3”. What will you recommend

if you are assigned Materials Engineer?

Reject the concrete design mix.

f beam samples taken from a newly paved section failed to meet

the strength requirement and it is not advisable to obtain cores from

structural due to structural consideration, as Materials Engineer what

will you do if the deficiency in strength of the concrete specimen is

15%?

Accept the section at an adjusted price due to strength

deficiency.

The improper compaction of an embankment material will _____

except:

Increase shear strength soil stability

The following properties of an asphalt mix can be determined in a

core sample except for:

Index of retained strength

In how many hours should concrete core samples be submerged in

water subjecting them to compression test?

At least 40

A concrete beam fails within the middle third at 7,000 lbs. The

flexural strength of the sample is:

680 psi

In the process of the compaction of Item 200 (Aggregate Sub-base)

which contains sandy material only 80% density was attained. What is

your recommendation in order to comply with the 100% minimum degree of

compaction?

Provide additional binder

The rate of application of emulsified asphalt used as tack coat

should be within.

0.2 to 0.7 liters/m2

The apparent omission of a detailed description or definition

concerning the quality of materials from the plans and specifications

shall be regarded to mean that:

None of the above.

Stability of an asphalt pavement is its ability to resist shoving

and rutting under traffic loads. In general higher stability of

the mix can be attained by using:

Angular and rough aggregates

The spot test on asphalt is used to determine:

Overheating during manufacture/production

What is used to measure pavement surface irregularity?

3 meters straight edge

The laboratory density of a bituminous mix is 97%. If the density

of a newly completed asphalt pavement is as 95%, what is the degree of

compaction?

98%

The following can be used to help stabilize earth slope except:

grass cover

The following test can be performed on disturbed samples taken

from soil exploration except for:

Consolidation Test

The workability of a bituminous mix is dependent on the:

Gradation of aggregates

In bituminous plant mix surface course the temperature of the mix

shall have an allowable tolerance of:

10°C

The rate of loading of the machine will somehow affect the

strength of the materials being test. The rate of loading that must be

observed when testing concrete cylinders specimen is:

20 to 50 psi/sec

When the top surface of a concrete specimen is rough and not truly

plane, stress concentrations are introduce and the strength of the

concrete is reduced by about?

1/5

During testing of concrete cylinders in uniaxial compression, what

will happen to the result of the test if the rate of loading is rapid

(i.e. way above the prescribed rate of loading)?

The computed compressive strength will be higher.

In hot climate, under sustained loading, asphalt cements behave

like:

Viscous liquids

Slurry System for road surface treatment of Item 304 A is a type

of:

Cold asphalt mixture

From the following data, determine the degree of compaction.

Field Density Test Data:

Weight of material taken from hole = 4,885 kg

Weight of sand to fill hole, kg = 3,885

Volume of hole, cu.m = 0.0028

Wet Unit Weight, kg/m3 = 1,663

Laboratory Data:

Maximum Dry Density, kg/m3 = 225

Optimum Moisture Content, % = 8.10

74

ASTM C-150 requires that the 28-day strength of mortar made from

Type I Portland Cement be at least 27.6 Mpa. Three specimens were

tested: Two passed but one failed by more than 20%. As a Materials

Engineer, what will be your conclusion?

Perform a re-test since the date is inconclusive.

Before concrete paving, the base of a road way should be kept in

moist condition and saturated with water for at least ____.

2 hours

Following are the results obtained from field density and

laboratory compaction test:

20%

In a plastic limit test, what is the diameter of thread soil

samples to be rolled by hand?

3.2 mm

How do you obtained the density of soil in the field?

By weighing the disturbed soil removed and obtained the

volume of hole sand or with other means.

Accreditation of Contractor’s/Consultant’s Material Engineer is

provided under Department Order No.,

D.O. No.141 series of 1999 – Accreditation of Contractors/

Consultant Materials Engineers

It is essential in soil mechanics work that drying ovens are

preset to a temperature of

105°C to 110°C

In pavement construction; what is the required density of the

bituminous mixtures based on laboratory density of the compacted

specimens?

Equal or greater than 95%

How many layers should a 40cm thick aggregate base course be

placed?

2

It is a type of emulsified asphalt that works better with wet

aggregate and in cold weather.

Cationic Emulsion

If the soil is not compacted as its maximum dry density, it will:

Increase permeability

What should be done on the sub-base course with existing moisture

content of 10% higher than the optimum moisture of AASHTO T-180 Method

D?

Dry out to reduce moisture, spread to the required loose

thickness and compact.

Materials suitable for embankment shall have a plasticity index of

not more than:

6

The concrete has been tested listed for consistency, after the

test, the height of the concrete was measured at 178mm. What is the

slump of the concrete?

122 mm

Which of the following is not part of the Marshall Method for

preparing and evaluating trial mixes?

The mixing and compacting temperature for the asphalt

cement to be used are obtained from the temperature –

viscosity

graph.

What penetration grade of asphalt material is appropriate for

sealing of PCCP joints,

Not exceeding 90

The correctness of effectiveness of all concrete mix design can be

checked by conducting a _______.

Trial Mix

Given:

Bulk volume of asphalt specimen = 500 cc

Weight of dry specimen in air = 1,200 g

Calculate the bulk specific gravity of the asphalt specimen

2.4

Which is not a type of PCCP distress?

Raveling

The temperature of concrete during the period of mixing while is

transport and/or during placing shall not be permitted to rise above:

36°C

.When the result of the second test differs from that of the first

tests on a sample representing the same lot of materials, a third test

is done. This is referred to as:

Referee Test

If the minimum compressive strength for concrete class A is 20.7

Mpa, what is the minimum compressive strength for concrete class C?

20.7 MPa

What is the permitted variation from the design thickness of a

layer aggregate sub-base course?

20 mm

Bituminous mixture shall have a minimum dry impressive strength

of,

200 psi

The DPWH requirement for asphalt pavement thickness acceptance is,

– 5mm

The result of the immersion test conducted in an asphalt mix

samples are as follows:

50%, No

The following are the measurement in cm of a concrete core taken

for thickness determination at station 0+100:23,24,23,23,24,24,23.

Actual measurement of the core at the center is 23cm. What is the

average thickness of the core if the designed thickness is 23cm?

23.22 cm

Soil sample was subjected to the following procedures at the

laboratory . a) Compaction at its optimum moisture content; b)

Application of surcharge (to the sample) to represent the estimated

thickness of pavement over the sub-grade; c) Soaking of the sample for

4 days and then; d) forcing a Plunger into the sample to a depth of

2.5mm. What test was conducted to under soil?

CBR test

In the 2013 edition of DPWH Standards Specifications for Highways,

Bridges and Airports Item 202 is about:

Crushed Aggregate Base Course

The fine-grained soils in the field can be identified through the

use of simple visuals and manual test except,

Dry Weight

Under what climate conditions do we use the lower penetration

grade of hard asphalts?

Hot Climate

The approval of preliminary samples from the same source shall:

Not be considered a guarantee of acceptance of all

materials from the source.

The minimum testing requirement for one quality test of concrete

hollow block is ______ units for every 10,000 units.

6

The shape of a compaction curve in a laboratory compaction test of

soil is a _______.

Parabolic

Peat and muck are considered as?

Highly organic soils

When using a nuclear density gauge, which of the following is not

a requirement?

Operator must wear thick clothes

The maximum percentage abrasion lose allowed for paving concrete

aggregate is,

40%

Stone Mastic Asphalt shall be placed at a temperature not less

than?

135°C

Permit for the procurement of chemicals used for various

laboratory testing can be secured from?

PDEA

Concrete curing refers to:

Procedure done to promote cement hydration.

The aggregate component contributes internal friction to shear

strength and stability of the bituminous mixture. The desirable shape

and surfaces texture of aggregate particles are:

Angular and rough-textured particles

The following are not purpose of driving test piles except:

To determine the required length

This is a test criterion for reinforced concrete pipe tested in a

three-edge bearing test?

0.3mm crack

The measurement of the thickness of an asphalt core using a

caliper is based on:

4 sides

A construction work progress, you noticed that the materials

delivered at the project site are different from the ones tested and

that passed the requirements. As materials engineer, what would you

do?

Conduct immediate re-testing of the materials for

verification purposes.

Testing of concrete samples may be done at an earlier age for

purposes of:

Determining the trend of its strength development

What test determines to deformation of a compacted asphalt

concrete mix?

Marshall Stability Test

If the bulk specific gravity of a bituminous mix is 2.342 and the

day stability is 3000 lbs, what is its index of retained strength if

its wet stability is 2400 lbs?

80%

The laboratory density of a bituminous mix is 2.233. What is the

degree of compaction of a 5cm asphalt overlay for which a field

density of 2.01 was obtained?

90%

A set of three core samples has the following compressive

strengths: 4000 psi, 3500 psi and 2600 psi. If the required strength

is 3500psi the area represented by the core is:

Not Acceptable

Sampling of soil aggregates in a big stockpile shall be done by:

Taking sample from the bottom, middle and top of the

stockpile.

In Item 311-PCCP, the dividing line between course and fine

aggregate is ______ mm sieve.

4.75 mm sieve

Samples of aggregate base course material when tested for quality

passed the requirements except grading what will you recommend as

Material Engineer.

Reprocess the material by blending

The following are not true regarding the rebound (Schmidt) hammer

test for concrete except:

It is simple and versatile test method which can be used

even on rough concrete surfaces.

Tensile strength, yield strength and elongation are the common

required test to determine the quality of:

Reinforcing steel bars

The sand used in the field density test in determining the volume

of hole using sand cone method must be clean, dry and passing sieve

number:

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