SEALANTSADVANCE CIVIL ENGINEERING MATERIALS(2721401)

M.E. Construction Engineering Management

(Semester II)

Prepared By:

Badatiya Pintu (140490714001)

Patel Vimal (140490714010)

Guided By:

Asst. Prof.

Rusabh Shah

CONTENTS• Introduction

• What is SEALANT?

• Functions

• Applications

• Types of Construction Sealants

• Advantages

• Common Problems OR Disadvantages

• Comparison with Adhesives

INTRODUCTION• The Early 1950s saw the application of the new concept of curtain-wall

construction in high-rise structures through out the world.

• This concept was based on the use of a skeleton of steel or concrete that was

then wrapped in a separate envelope or non bearing curtain wall.

• This reduced the use of the low-rise bearing wall type construction and

introduced greater flexibility in design through the use of precast concrete

panels, glass or metal panels, unit masonry, and combinations of these

materials.

• Construction was also become much faster, also these

structure are inherently more flexible than bearing-wall

construction, but present new problems in weather

proofing.

• The introduction of the curtain wall was accompanied by the introduction ofelastomeric sealants that would adhere to the various surfaces and takegreater movement than had existed in the older expansion joints.

• The old oil-based caulking compounds no longer qualified, and the newmaterials became “SEALANTS” rather than caulks.

• However, the term “SEALANT” has been too broadly used and nowincludes a wide assortment of weather proofing joint materials.

• Sealants or caulking compounds include viscous liquids, pastes, tapes,gaskets, and even water proofing membranes.

• The materials can either cure to a rubber or remain in a mastic stage.

What is SEALANT?

• The Layman’s definition of ‘SEALANT’ is “any material placed in a

joint opening generally for the purpose of weather proofing a building,

so designed to prevent the passage of moisture, air, dust, and heat

through all joints and seams in the structure.”

OR

• The ASTM Committee C-24 definition for ‘SEALANT’ is “in building

construction, a material that has the necessary adhesive and cohesive

properties to form a seal.”

Functions• Sealants, despite not having great strength, convey a number of properties. They seal

top structures to the substrate, and are particularly effective in waterproofing

processes by keeping moisture out (or in) the components in which they are used.

• They can provide thermal and acoustical insulation, and may serve as fire barriers.

• They may have electrical properties, as well. Sealants can also be used for simple

smoothing or filling.

• They are often called upon to perform several of these functions at once.

• A corking sealant has three basic functions: It fills a gap between two or more

substrates; it forms a barrier through the physical properties of the sealant itself and

by adhesion to the substrate; and, it maintains sealing properties for the expected

lifetime, service conditions, and environments.

• The sealant performs these functions by way of correct formulation to achieve

specific application and performance properties.

Applications• Horizontal and vertical metal-to-metal and masonry-to-masonry expansion

and control joints

• Dissimilar material joints, such as metal-to-masonry or concrete-to-wood

• Joints between precast concrete façade panels

• Spandrels

• Perimeter of doors and fixed window frames

• Exposed exterior masonry control joints

• Expansion or control joints in curtain wall

• Joints in exterior walls

• Concealed masonry-to-floor structure joints

• Repair of larger cracks

SEALANTS

Types of Construction Sealants• Silicone Sealants

• Epoxy

• Hybrid Polyurethanes Sealants

• Polyurethanes Sealants

• Elastic Sealants

• Varnish

• Acrylic Latex Sealants

• Bituminous Sealants

• Synthetic Rubber Sealants

• Thermoplastics Sealants

• Butyl Sealants

• Hot Wax

• Proof Sealants

• Polysulfide Sealants

Silicon Sealants Butyl Sealants

Epoxy Sealants

Bituminous Sealants

Elastic Sealants

Advantages

• Improves Product Durability and Reliability.

• Increases Product Performance.

• Increases Design Flexibility.

• Increases Product Quality.

• Enhances Product Aesthetics.

• Improves Process Productivity and Reduced Manufacturing Costs.

• Increases weathering characteristics.

Common Problems ORDisadvantages

• Deterioration of sealants causes due to prolonged exposure to water, ultraviolet light,

and freeze-thaw cycles.

• Loss of Adhesion caused by the presence of coatings or contaminants that prevent

proper adhesion.

• Cohesive failure due to deterioration of the internal integrity of the sealant; cracking

parallel to the interface of the joint is an indication of this type of failure.

• Inappropriate Choice of Sealant and Improper Joint Design may fail the joint and

losses the adhesion.

• Uncured Sealant that is uncured is often due to incomplete or improper mixing of the

sealant components, or from using materials that have outlived their shelf life losses

the adhesion and fails the joints.

• Bubbling and Blistering of the Surface losses the adhesion and fails the joints.

Comparison with Adhesives

• The main difference between adhesives and sealants is that sealantstypically have lower strength and higher elongation than adhesives do.

• When sealants are used between substrates having different thermalcoefficients of expansion or differing elongation under stress, they needto have adequate flexibility and elongation.

• Sealants generally contain inert filler material and are usuallyformulated with an elastomer to give the required flexibility andelongation.

• They usually have a paste consistency to allow filling of gaps betweensubstrates. Low shrinkage after application is often required.

• Many adhesive technologies can be formulated into sealants.

THANK YOU…