Extreme environmental conditions during the pouring and curing of concrete significantly affect its mechanical properties, leading to potential construction delays if not managed properly. Research indicates that increased temperatures and moisture levels can substantially decrease both compressive and tensile strength, with a notable 38% reduction in compressive strength observed at 80°C. Proper curing practices and considerations of these environmental impacts are essential for ensuring the durability and structural integrity of concrete structures.

1. introductio
n
• Concrete's mechanical and physical properties
are significantly influenced by the
environmental conditions during pouring and
curing. Extensive research shows that
extreme conditions—cold, dry, damp, humid,
hot—impact its curing process. Construction
may need to be delayed unless precautions
like heating or wetting surfaces are taken. The
main concern is how cured concrete behaves
under varying conditions. Studies indicate
that changes in temperature and moisture
affect concrete's compressive strength and
elasticity. For example, Lawson et al. [12]
found a 100°C rise in temperature causes a
50% loss in compressive strength. Proper
curing practices are essential for the
durability of concrete structures.

2. Procedure
Specimen preparation
• 137 specimen cylinders were
made
• 71 of them have diameter 0.15
m(6 in) and height of 0.305 m (12
in.)
• And others have diameter of 0.10
m (4 in.) and a height of 0.2 m (8
in.)
Enivronmental chamber
• environmental chamber was
designed to be capable of
producing temperatures between
-30C and 55 C to store the
concrete specimens to measure
the stress–strain relation of the
concrete under different
temperatures and moisture levels

4. Concrete Compressive and Tensile
Strength
• Standard concrete cylindrical specimens were tested at various
ages to measure strength gains over time, with tests conducted
at a constant 20°C. Three specimens were tested for each time
interval in both compression and tensile tests. Results show that
concrete strength increases rapidly at first and then slows down
by day 14, following the typical pattern of concrete strength
development.
• Compression and split tensile tests on day 28 showed that
concrete strength decreases as temperature rises. An 80°C
increase in temperature reduced compressive strength by 38%
and tensile strength by 26%. The strength-temperature data
followed linear relationships

5. Modulus of elasticity and Poisson’s
ratio
• Instrumented concrete cylinders were tested in
compression at different ages to measure the modulus of
elasticity and Poisson’s ratio. To ensure even load
distribution, the cylinder ends were smoothed, aligned with
the machine axis, and covered with rubber pads. Load was
gradually applied and removed from 0 to 45 kN using a 225
kN capacity load cell. The stress-strain data obtained were
used to calculate the modulus of elasticity and Poisson’s
ratio.

7. RESULTS

11. CONCLUSION
• Temperature and moisture
significantly impact concrete
properties. In the study's range of -
20°C to +50°C, higher temperatures
and moisture levels degraded
concrete strength and modulus of
elasticity, though Poisson’s ratio was
unaffected. Concrete curing initially
reduced thermal expansion and
strength but eventually increased
compressive and tensile strength and
modulus of elasticity. These changes
should be considered in concrete
structure design due to their influence
on structural behavior, strength, and