INTERNAL CURED CONCRETE COVER BLOCK USING SUPER ABSORBENT POLYMER

Abstract

This research focuses on the development and analysis of internal cured concrete cover blocks using Super Absorbent Polymers (SAP). Concrete cover blocks play a crucial role in maintaining the necessary spacing between reinforcing steel and the exterior environment, ensuring durability and structural integrity. Traditional concrete often suffers from shrinkage and cracking during curing, which can compromise the cover block's performance. To address this issue, internal curing using SAP is explored as an innovative approach. Super Absorbent Polymers are introduced into the concrete mix to absorb and retain water during the curing process, releasing it gradually as the concrete hardens. This internal curing mechanism helps to mitigate the effects of autogenous shrinkage, reduce cracking, and improve the dunibility of the concrete cover blocks. The study investigates the mechanical properties, water retention capacity, and shrinkage behavior of the SAP-modified concrete cover blocks. Experimental results indicate a significant improvement in shrinkage control, moisture retention, and overall durability compared to conventional concrete cover blocks. The findings suggest that SAP-enhanced cover blocks can extend the service life of reinforced concrete structures by reducing early-age cracking and enhancing long-term durability. This innovative material has the potential to improve the performance and sustainability of concrete infrastructure, particularly in environments where moisture retention and shrinkage control are critical.

Specification

PREAMBLE TO THE DESCRIPTION
THE FIELD OF INVENTION (PACKAGING INDUSTRY)
The invention pertains to innovative advancements in the construction industry, specifically in the
areas of mortar, concrete and curing.
BACKGROUND OF THE INVENTION
Curing is a vital step in the concrete making process, without which required strength cannot be
achieved. However, this step is mostly ignored or not given importance at the layman level due to
lack of awareness.· Internal. curing is a method of self-curing mortar or concrete from the inside
through materials which have the ability to absorb and release the reserved curing water when there
is a drop in the internal relative humidity of the surroundings. Providing curing water externally
penetrates the concrete only to a certain distance where the interior of the concrete lacks sufficient
curing water. This might reduce the rate of hydration, whereas internally curing the concrete with
curing agents/water retaining materials to hold water which is not part of the mixing water helps in
uniform distribution of the curing water throughout the mass. Th,e basic requirements of any internal
curing material are absorption and desorption. The absorption capacity of the material is of prime
concern since the amount of water to be provided for internal curing depends on the absorption
capacity. Similarly, desorption is the ability of the material to de-absorb the retained water. If the
material taken for internal curing has a high absorption capacity and very less or no desorption
capacity, the extra water added remains in the concrete as free water and aids in the disintegration
of the concrete. Hence any material chosen for internal curing should satisfy both these
requirements .


SUMMARY OF THE INVENTION
Internally cured concrete cover block using super absorbent polymer is invented to enhance the
curing of concrete cover block in building construction.


COMPLETE SPECIFICATION
Specifications
• The absorption capacity of super absorbent polymer is found using the tea bag test
The weight of the sample with the tea bag was calculated using a known quantity
of dry sample that was obtained and placed in a dry tea bag. As soon as a constant
mass was reached, the weight of the sample containing the tea bag was recorded.
The absorption capacity of the SAP sample was found to be 125 mil g.
• The time-dependent absorption of SAP was also found by Tea-bag test at different
time intervals. The water absorption increased till saturati6n was reached. The time
at which the water attains saturation is called swelling time and it was found to be
600 s.
• The dosages of super absorbent polymers were determined by the chemical
shrinkage of the paste. Based on factors like absorption capacity of the curing
material, chemical shrinkage of paste and the expected degree of hydration, the
volume of internal curing material was determined. The dosage of super absorbent
polymer was found to be 0.85 - 1.1 %.
• The concrete cover block were casted and tested using compression test machine_
• The establishment of internally cured concrete cover block using super
absorbent polymer.


DESCRIPTION
Super absorbent polymers are cross-linked polymers of acrylic sodium salt which can absorb and
retain water up to 500 times its own weight. These have found their widest applications in the
hygiene industry and agricultural industry. Since they have a very high affinity towards water and
aqueous solutions, they are used to absorb water and for controlled release. They are water swell able
and form a gel with the addition of water. When water is added to the super absorbent polymer an
osmotic pressure is developed, and the cross-links present in the super absorbent polymer molecules
prevent the water to diffuse through the membrane hence the polymer molecules do not dissolve in
water but swell over time. The absorption and retention capacity of the polymer molecules depends
upon many factors such as particle size, type of cross-linking, method of polymerization, presence
of ions in the solute, etc. The type of polymer taken for this study was a solution polymerized acrylic
salt of sodium ions with a particle size of I 00 to 150 micron.

CLAIM
We Claim
I. Claim: Internally curing agents replaces the conventional external curing of concrete cover block.
2. Claim: Super absorbent polymer as internal curing agent serves the water required for
hydration of concrete cover block.
3. Claim: The I% super absorbent polymer is the optimum dosage for internal curing of concrete
cover block.
4. Claim: The super absorbent polymer can be utilized to cure the concrete cover block mix
internally.

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