6. BRICK AND CONCRETE BLOCK WORK
6.1 Scope of work
Furnish all labour, material
and equipment for the complete
building of brick and
concrete block work as shown on the drawings, as specified
herein and as evidently
necessary to complete the work.
6.2 Submittals
Before starting
the work the contractor shall submit the following
to the Engineer and receive
his written approval.
6.2.1 Manufacturer and sample blocks
Before precasting concrete block, the name and official address
of the concrete block
manufacturer, if the contractor intends to use a sub, contractor, sample block and sources of cement and aggregate making up the concrete block shall be submitted to the Engineer
for his written approval.
report
6.3 Materials
6.3.1 Masonry brick
Brick shall be locally available products conforming
to D.S. 3921 or equivalent
and be hard, well baked
and
shall
have
a
uniform
and
sufficient
compressive
strength
appropriate to the use. The shape of the bricks shall be rectangular. Brick used in foundation shall be misakhraj brick or
equivalent.
6.3.2 Concrete
blocks
All concrete
blocks shall conform
to ASTM C129,
B.S 2028 or equivalent unless otherwise specified as follows:
a. Concrete block shall be manufactured in accordance with the specification stated herein,
b. block shall be manufactured of Portland cement and locally available aggregate by mixing and compacting using
an electric machine,
c. block shall be reasonably uniform in compressive strength and in all dimensions and shall be straight and free
from cracks, chips or other defects.
Specification of the materials
shall be in accordance with section ( 4_2), " Concrete
work "
6.3.3 Joint mortar materials
a. cement
cement shall be specified in section 4_2_1 ( concrete work)
b. Sand
Sand shall be clean sharp, coarse, well _ graded and shall conform to ASTM C-144 (
Aggregate for Mrrary jortar ) or B»S. 1200 ( Building
sand from Natural aourcec)
c. additive
water proofing
additive shall conform
to B.S 3826 or equivalent, other admixtures, such as a type which reduces early water loss from the masonry units and produces
an expansion action in the plastic grout sufficient to off_set initial
shrinkage and promote bonding
of the grout , may be used when approved by the Engineer.
6. 4 Workmanship
6.4.1 The contractor shall provide a masonry foreman who is thoroughly
experience, competent and skilled in masonry construction .
The foremen
shall personally supervise
the mixing and placing of all mortar.
Masonry reinforcing and anchoring must be done in strict
accordance with the drawing and specifications.
6.4.3 Mixing of joint Mortar
a. Standard
proportion of mortar
mix for the joint of bricks and blocks shall be:
cement to sand = 1:3, or as directed by the Engineer,
sulphate resisting cement shall
be used in mortars below damp proof
course
b. Mixing
i. Mix mortar by mechanical mixer or by hand
on a clean level board.
ii. mix thoroughly so that all individual constituents are incorporated evenly but do not over-mix mortars containing plasticizers.
iii. Keep mixer clean at all times.
iv. Use mortar with in one hours of discharge from mixer at normal taaporturo
. In no case chalj nortor be used after the initial set has taken place. Reconstitution of mortar will not
permitted.
6.4.4 Laying units
All work shall be laid true to dimensions and be plumb, square in bond and properly anchored with vertical and horizontal straight joints
that are in line,
plumb, horizantal and true . Brick laying for protective chin for waterproofing memberane shall be laid
in running bond with standard 2_3mm joints horizontally and vertically. All surfaces of waterproof memberane to receive
briek laying shall be throughly
domed masnory mortar shall be spead over the cntir surface
of joints. laying out of the bricks shall be
arranged so that vertical joint are staggered Salf bricks or other shapes shall be used
where required, All hollow
block
shall
be
laid
cells
vertical
and
with
full
nortar
coverage on all top and side faces,
horizontally and vertically.
Cells of hollow blocks to
be grouted with concrete or nortar are those carrying
the horizontal and vertical
reinforcement and also abutting cells, with or without reinforcing, cells of hollow
block forming the cider, of entrances and doorways and cantilevered fins of walls and
those so indicated on the drawings or so required
by the Engineer.
In Icying concrete solid
blocks, pounding of comers and jambs after units liave been set in position
shall be avoided,
where an adjustment must be made after the mortar lias startde to cat, the mortar shall
be removed and replaced with fresh mortar, colls of unfinished ends
shall
not
exposed,
Bond
all
interesting
masonry
walls
together as indicated or a approved by the Engineer,
When
necessary
to
out
masonry units, preference must be given to the use of power oquipreiit . Cutting shall be
kept to a minimum.
A protective covering of mortar
shall be fornecl
around the reinforcing bars at a minimum
depth of 20 mm, laying
for brick work shall be as shown
on the drawings. when it in not specified
on the drawings, the contractor shall follow the instruction of the Engineer.
Joints of masonry units which will be exposed
or painted. form a concave
joint section.
Joints which are not to bo visible in the finished
work to be dtruck off with the trowel
as the work proceeds.
joints on the oufaces of fair_faced
work shall be finished
to provide as mooth surface flush with the brick and or block
face or a keyed joint of approved profile aa the work proceeded
All hole in corposed rjasomy
shall be repaired, and the walls pointed. Defective
joints shall be trowelled out and repointcd with nortar.
A much needed guide for those who are new to the trade, masonry and roofing. A great start for rookies!
ReplyDelete-Adam Ahmed