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Structural joints in building construction

Properties of a good sealant

1. Protection

2. Durability

3. Less expansion

4. Good adhesion

5. Chemical inertness

6. Sound insulation - Air tight

7. Must be of softer grade and not stiff

8. Good wetting behaviour

9. Must be able to absorb thermal stresses

Characteristics and Properties of good Joint filler materials

The followings are the different requirements of good joint fillers.

• The ability to create an effective water seal.
• It should absorb the impact and shock of heavy loads and steel wheeled traffic, preventing erosion of control joint edges.
• The ability to expand and contract, as the joint widens or narrows in response to environmental or other conditions, while maintaining an effective seal against the sides of the joint.
• It should be durable and economical
• The ability to flex in every direction, as the joint flexes due to structural conditions, loading, or environmental conditions, while maintaining an effective seal against the sides of the joint;
• It must give aesthetically acceptable appearance; the capability of being installed in a joint by fairly unskilled labor;
• It must posses' long life, Wear resistant, durable and resilient; it does not harden or become brittle with age.
• The ability to adhere to numerous surface materials, such as concrete, steel, or aluminum without extensive or expensive surface preparations.
• The ability to fit into joints of a large variety of widths.
• It must posses' Small density, high recovery rate, with independent air bubble structure.
• Low surface water absorption rate with good seepage resistance.
• Good resistance to corrosion of acid, alkali, salt and oil among other organic solvents and good resistance to aging.
• No flowing under high temperature and no cracking under low temperature.
• Flexibility provides for joint movement and protects slabs edges from chipping Cures on damp or wet surfaces
• Penetrates and fills without running
• Flexible enough to absorb hard heavy wheeled traffic.
• The ability to reduce stress cracking and telegraphing.
• The ability to bonds tightly to the sides of the concrete joint prevents contaminant penetration and delivers high wear resistance and durability.
• It should be environment friendly.
• It must have uniform consistency with no measurable shrinkage.
• It must posses' adequate tensile strength. As tensile strength relates to the capacity of this material to hold together when stretched. Percentage tensile elongation is the length the material can be stretched before failure.
• It must deliver adequate support to joint shoulders receiving the force of hard wheel traffic carrying heavy loads.
• Delivers tight bond to faces of joint

Related Pages	Related pages
Foundations	Dampness and Damp proof cement (D.P.C)
Joints	Reinforced Cement Concrete Design
Building construction and maintenance	Formwork
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