Question 1/ (10pts)
a) What do you understand by Bill
of Quantities? Qu’est ce que vous entendez par devis
quantitatif?
b) Civil engineers use standards
codes to design structures; give two (2) of them. / Les
ingénieurs civil utilisent
des codes de normes pour concevoir les structures. Donnez deux
d’entre elles.
c) Give the difference between
a master builder and a master of construction work. /Donner
la difference entre maitre
d’oeuvre et maitre de l’ouvrage.
Answer1:
a) This is a statement of various
items of works giving the description, quantities and unit
rates. The column of rates is normally left unfilled
to be filled by contractors. (4pts)
b) British standards, European,
ISO standards, American standards, Chinese standards,
Japanese standards, Australian and New Zealand
standards. (2pts)
c) Master builder.: A person who has attained proficiency in one of the building crafts
and
is qualified or licensed to supervise building
construction.
Master of construction work is the client.
(4pts)
Question 2/ (15pts)
The quantity of concrete needed
in foundation work is 140 m3; considering the ratio 1:2:4 for the
mixture, Calculate the quantity
of cement, fine aggregate and coarse aggregate needed/
La quantité du béton qu’on doit utiliser dans la foundation est de
140 m3 ; en considerant la
repartition des ingredients égale a 1:2:4 du mélange. Calculer la quantité
du ciment, du sable et
du gravier
Answer 2:
The ratio is 1:2:4 = 7 parts.
Then the amounts required for concreting
materials are worked out by first valuing 1 part,
i.e.: 140 m3 /7 = 20 m3
Therefore, cement is 1 part of
20 m3= 20 m3 (2pts)
And the fine aggregate is 2 part
of 20 m3 = 40 m3 (2pts)
And the coarse aggregate is 4 part
of 20 m3 =80 m3 (2pts)
Check 140 m3
a) Cement quantity:
As the cement is approximately 1500 kg/m3,
Hence, 1500 kg/m3 ×20 m3=30,000 kg of cement
Add for decrease in volume and waste 42.5%
=12,750
b) Fine aggregate:
Fine aggregate required is40 m3
Add 50% for decrease in volume and waste =
20 m3
60 m3
As the aggregate is approximately 1500 kg/m3,
Hence 60 m3 × 1500 kg/m3 = 90,000kg = 90 tons of fine aggregate required. (3pts)
c) Coarse aggregate:
Coarse aggregate required is80 m3
Add 50% for decrease in volume and
waste = 40 m3
120
m3
the aggregate is approximately 1500
kg/m3,
therefore, 120 m3 × 1500 kg/m3
= 180,000 kg = 180 tons
of aggregate required (3pts)
Question 3:
Give five types of flexible pavement failures/defects,
their causes and
remedial measures / Donnez cinq types de défaillances ou défauts des chaussées asphalté,
leurs causes et les mesures correctives.
(25pts)
Answer 3:
a) Corrugation/shoving:
These are in the form of
plastic movements typified by ripples (corrugation)or an abrupt
wave (shoving) across the
pavement surface. (2pt)
Causes: - mix contamination; (1pt)
- poor mix design (segregation). (1pt)
Repair: resurfacing (1pt)
b) Bleeding:
It is a film of
asphalt binder on the pavement surface which usually create a
shiny, glass-like reflecting surface that can become sticky when
dry and slippery
when wet. (2pt)
Causes: - Excessive asphalt binder in the surface layer (poor mix
design);
(0.5pt)
-Law surface layer, air void content. (0.5pt)
Repair: - Minor
bleeding can often be corrected by applying coarse sand to
blot up the excess asphalt binder; (1pt)
-Major bleeding can be corrected by cutting off excess asphalt and
resurfacing. (1pt)
c) Polished aggregates:
This is characterized
by the areas of the wearing course with the portion of
the aggregate extending above the asphalt binder being either very
small or they are
no rough angular aggregate particles. (2pt)
Causes: - Repeated traffic applications; (0.5pt)
- Use of aggregates susceptible to abrasion. (0.5pt)
Repair: - Slurry sealing; (0.5pt)
-Resurfacing; (0.5pt)
-Non-structural overlay. (1pt)
d) Alligator cracking:
These are series of interconnected cracks caused by fatigue of the
surface layer under
repeated traffic loading. (2pt)
Causes: - Repeated traffic loading; (0.5pt)
- Stripping; (0.5pt)
- Poor construction (inadequate compaction). (0.5pt)
Repair: - Sealing; (0.5pt)
-Overlaying; (0.5pt)
-Patching. (0.5pt)
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