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A bond breaker may be defined as a separator substance spread in between adjoining solid surfaces to make sure that there is no adhesive molecular bond between the surfaces.
Bond breakers are majorly utilized for tilt-up walls and precast components so that the proper components are cast together. They can be any flexible sealants in the state of liquid, spray, rods, or tapes.
1. Uses of Bond Breaker
The uses of bond breakers are as follows:
a. It is employed to control cracks, which may occur in concrete surfaces due to temperature changes.
b. They are used in splitting the bond between the substrate and waterproofing membrane system, thus creating an adjustable bridge, opposing the motion of water or moisture.
c. It is used to enhance joint performance.
d.They are employed to withstand shrinkage cracks, which may occur on the concrete during casting, due to the incredible evaporation of water from the concrete surface.
2. Materials Used in Bond Breaker
Bond breaker materials are categorized into many forms, such as:
Liquid bond breakers are commonly employed as crucial bond breaker materials. In a few countries, petroleum-based materials have been in utilize.
Still, these chemicals also extremely affect the properties of the concrete members, so this compound is not known in all countries.
Not very much in usage. Liquid bond breakers are chosen over bond breakers in spray form.
Many a time, rods with a coating of specific chemical compounds, wife mesh, have been utilized as a bond breaker.
Not very much in usage in the current construction industry, due to insufficient professional understanding and lack of evaluation of side effects.
Bond breaker tape is self-adhesive polyutherene tape, containing black color, which holds comfortability hugely to irregular surfaces.
These tapes are utilized for isolating sealant and removing sealant adhesion to concrete and metal.
It controls the sealant from attaching to the surfaces and controls three-sided adhesion.
To control the sealant from attaching to the surfaces, bond breaker tape is involved along the whole width/length of the base of the joint.
Bond breaker tapes are obtainable in the mentioned width:15 mm, 20 mm, 25 mm, and 50 mm.
Wax is a commonly used bond breaker material in different countries. But, it also has a few drawbacks, still famous as an effective bond breaker material.
3. Features of Bond Breakers Used in Construction
They are anti-stick materials employed on adjacent metallic or non-metallic substrates, such as concrete and steel.
They can be employed to enhance joint performance. Without it, the joint sealer rips apart to accommodate movement.
A bond breaker tape in between the joint sealant and joint filler is delivered to promote free movement.
They are employed to split the bond between the substrate and the waterproofing membrane, composing an adjustable bridge, which opposes the movement of water or moisture.
Bond breakers decrease the uneven dynamic loads on the precast segments at the time of their lifting and stripping from the casting molds.
They are also involved on concrete surfaces to decrease the cracking of slabs induced due to temperature and moisture changes.
4. Types of Bond Breaker
The types of bond breakers are mentioned below:
a. Membrane-Forming Bond Breaker
b. Non-Membrane Forming Bond Breaker
This type of bond breaker carries water into the casting slab. Whenever a casting of the slab is accomplished, it needs a sufficient amount of water, so that the chemical reaction between cement and water can advance uninterruptedly.
Many times, due to evaporation and due to various atmospheric circumstances, there is insufficient water.
To control that for precast slabs, membrane-forming bond breakers are involved so that they can maintain the water, essential for the chemical reaction. This type of bond breaker is constructed of crude resins.
B. Non-Membrane Forming
This type of bond breaker is normally different from that of the previous one. This type of bond breaker does not create a membrane that can maintain the water.
Non-membrane forming bond breakers are divided into two categories are listed below:
2. Non Reactive
This type of bond breaker will mix with water and create a crude soap.
This type of bond breaker will contact with the concrete surface and will make a waterproof film.
5. Advantages of Bond Breakers in Construction
The advantages of bond breakers in construction are as follows:
a. It reduces the time required to move heavily loaded precast elements.
b. It does not affect the characteristics of concrete surfaces.
c. Their usage does not require any repainting or change to other architectural details.
d. The use of these breakers does not impact the bonding of adhesives, epoxies, or any other floor finishes.
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