3. The concrete mix gets severely affected by rains if the
concrete has yet to reach its initial setting time (30min).
When the concrete is between its initial setting time
and final setting time, rain merely affects the
appearance of the concrete leaving patch marks all
around. However, if the intensity of the rainfall is high,
the mix in the upper layer of the concrete may get
disturbed. After the concrete has reached the final
setting time (10hrs), rainwater turns into a source for
curing the concrete.
Er.RAJNISH YADAV
TECHNICAL NOTES
CONCRETING IN RAINY SEASON
4. With the increased humidity(in the environment) and
wetness of the raw materials (aggregate and sand), be
particular about the amount of water that is going into
the mixture. Excess water should be compensated to
stay within the Design mix’s limit. Water-cement ratio
can also be reduced by mixing suitable admixtures if the
client permits.
Water Content in the mixture
Er.RAJNISH YADAV
TECHNICAL NOTES
5. The use of hydrophilic crystalline admixtures when laying
the concrete provides concrete with the resistance to
infiltration of water under hydrostatic pressure. The
admixture reacts with water and cement particles to form
calcium silicate crystals that block both the pores and
microcracks in the concrete, preventing the passage of
water. This reaction goes on for the entire life of concrete,
serving to seal not only initial shrinkage cracks but also
cracks that occur over time.
Waterproofing Admixtures
Er.RAJNISH YADAV
TECHNICAL NOTES
6. When you are preparing to pour concrete, make sure the
weather conditions are not overly wet or windy. It is
recommended to pour concrete when there has been
more than 12hrs of dry weather.
Timing
Er.RAJNISH YADAV
TECHNICAL NOTES
Combat Heavy winds
Strong and resilient shuttering should be ensured before
pouring concrete. Heavy winds may cause bleeding which
may lead to shrinkage cracks.
7. In order to avoid traffic jams and congestions, the best
accessible routes for RMC trucks should be figured out
in advance. As most of the RMC trucks have an open
top, any delay in the delivery may allow surplus water
into the chamber, therefore, spoiling the concrete mix.
Transportation of Concrete
Er.RAJNISH YADAV
TECHNICAL NOTES
8. Plastic tarpaulins and rainproof canvas should
be brought to the site in advance at the time of
placing concrete. The covering of the area where
the concrete is to be poured should be done
keeping in mind the space to compact and finish
the concrete surface. If possible cover the heaps
of aggregate too, as when they become wet;
they increase the water-cement ratio.
Assisting Covers OF Concrete
Er.RAJNISH YADAV
TECHNICAL NOTES
9. After the rainstorm tames down, assess the damage
caused to the concrete surface visually. A simple scratch
test can be conducted to compare the relative surface
scratch hardness of areas in question to those slab
sections known to be of good quality. A thorough and
quantitative check requires you to take several core
samples and checking them in a lab with an electronic
microscope.
Visual Inspection
Er.RAJNISH YADAV
TECHNICAL NOTES
10. If the surface quality of the concrete is found to be
compromised, minor reparations should be made
immediately after the rain stops. Singular repairs can be
made using some of the same concrete or spraying
cement slurry on the surface.
If a lot of small areas of a thin slab are damaged, it
would be economical to remove and replace the
complete sections. If there is a large isolated area in a
thick slab with damage, a thin application of cement
slurry could be applied after the damaged concrete is
removed.
Instant Repairs
Er.RAJNISH YADAV
TECHNICAL NOTES
11. TO ALL CIVIL ENGINEERS
Er.RAJNISH YADAV
7574815531+9799405460
