24. 24
Deflection in a structure without widespread cracking,
spalling, or corrosion is frequently due to concrete
creep.
المبانى فى للعيوب الرئيسية المظاهر
اإلنشائية العناصر فى الترخيم
40. 40
Flow Chart of Retrofit Design
Site Investigation
Structural Analysis
Check if As of Beams & Columns is enough
No. of Insufficient Members
Detailed design
Retrofit design of structural system
Re-structural analysis
Check if As is enough
Retrofit design of structural system
Re-structural analysis
Check if As is enough
huge
Less
46. 46
Chisel out the crack
to create a
backward-angled
cut, using a cold
chisel and a
hammer.
المنشآت فى الشروخ معالجة
تطبيقى مثال
47. 47
Clean loose material
from the crack using a
wire brush, or a
portable drill with a wire
wheel attachment.
المنشآت فى الشروخ معالجة
تطبيقى مثال
48. 48
Apply at thin layer of
bonding adhesive to
the entire repair
area using a paint
brush. The bonding
adhesive helps keep
the repair material
from loosening or
popping out of the
crack.
المنشآت فى الشروخ معالجة
تطبيقى مثال
49. 49
Mix vinyl reinforced
patching compound,
and trowel it into the
crack. "Feather" the
repair with a trowel,
so it is even with the
surrounding surface.
المنشآت فى الشروخ معالجة
تطبيقى مثال
50. 50
Chisel out the crack and clean
loose material from the crack
as listed above. Then pour
sand into the crack to within
1.3 cm of the surface. Prepare
sand- mix concrete, adding a
concrete fortifier, then trowel
the mixture into the crack.
Feather until even with the
surrounding surface using a
trowel.
المنشآت فى الشروخ معالجة
تطبيقى مثال
51. 51
Cracking in concrete can be reduced significantly
or eliminated by observing the following
practices:
1. Use proper subgrade preparation, including
uniform support and proper subbase material at
adequate moisture content.
2. Minimize the mix water content by maximizing
the size and amount of coarse aggregate and use
low-shrinkage aggregate.
الخرسانة؟ فى الشروخ تجنب كيفية
52. 52
3. Use the lowest amount of mix water required for
workability; do not permit overly wet
consistencies.
4. Avoid calcium chloride admixtures.
5. Prevent rapid loss of surface moisture while the
concrete is still plastic through use of spray-
applied finishing aids or plastic sheets to avoid
plastic-shrinkage cracks.
6. Provide contraction joints at reasonable
intervals, 30 times the slab thickness.
الخرسانة؟ فى الشروخ تجنب كيفية
53. 53
7. Provide isolation joints to prevent restraint from
adjoining elements of a structure.
8. Prevent extreme changes in temperature.
9. To minimize cracking on top of vapor barriers,
use a 100-mm thick (4-in.) layer of slightly damp,
compactible, drainable fill choked off with fine-
grade material. If concrete must be placed directly
on polyethylene sheet or other vapor barriers, use
a mix with a low water content.
الخرسانة؟ فى الشروخ تجنب كيفية
54. 54
10. Properly place, consolidate, finish, and cure
the concrete.
11. Avoid using excessive amounts of
cementitious materials.
12. Consider using a shrinkage-reducing
admixture to reduce drying shrinkage, which may
reduce shrinkage cracking.
13. Consider using synthetic fibers to help control
plastic shrinkage cracks.
الخرسانة؟ فى الشروخ تجنب كيفية
56. 56
The crack is lightly
scored and cleaned out
with a diamond blade
attached to an electric
grinder. Dust and debris
is removed with a
vacuum.
حالة دراسة
57. 57
Concrete Mender is
applied to the crack
then a 0.6 cm Layer of
silica sand is applied.
حالة دراسة
58. 58
Repairs are made full
depth. Silica sand is
added to stop
"sinkers"
حالة دراسة