Advantage And Disadvantage Of Composite Construction

1. INTRODUCTION

A structural member composed of two or more dissimilar materials joined together to act as a unit as known as composite. An example in civil structures is the steel-concrete composite beam in which a steel wide flange shape is attached to a concrete floor slab. The many other kinds of composite beam include steel-wood, wood-concrete and plastic-concrete or advanced composite materials-concrete.

There are two main benefits of composite action in structural members. First, by rigidly joining the two parts together, the resulting system is stronger than the sum of its parts. Second, composite action can be better utilize the properties of each constituent material. In steel-composite beams, for example, the concrete assumed to

In conventional composite construction, concrete slabs are simply rested over steel beams and supported by them. These two components act independently under the action of loads, because there are no connection between the concrete slabs and steel beam.

The basic concept of composite beam lies in the fact that the concrete is stronger in compression than steel (which is susceptible to buckling under compression) and steel is stronger in tension.

1.2 Advantages of composite beam:

• The concrete and concrete is utilized effectively

• More economical steel section is used in composite construction than conventional non-composite construction for the same span and loading

• Depth and weight of steel beam required is reduced.so, the construction depth also reduces increasing the headroom of the building

• Composite beams have higher stiffness, thus it has less deflection that steel beams

• Composite beams can cover for large space without the need of any intermediate columns

• Composite construction is faster because of using rolled steel and pre-fabricated components than cast-in-situ concrete

• Encased steel beam have higher resistance to fire and

For finding specific gravity of cement kerosene is used

Specific gravity of cement is 3.13

5.1.2 SETTING TIME TEST OF CEMENT Initial and final setting time on cement is obtained by vicat’s apparatus, for the initial setting time of the cement vicat’s needle should penetrate to a depth of 33-35mm from the top, for final setting time the vicat’s needle should pierce through the paste more than 0.5mm. We need to calculate the initial and final setting time as per IS: 4031(part5)

Initial setting time of cement: 30mins

Final setting time of cement: 60mins

5.1.3 STANDARD CONSISTENCY TEST The standard consistency test of a cement paste is defined as that consistency which will permit vicat plunger having the 10mm diameter and 50mm length to penetrate a depth of 33-35 from the top of the mould. The basic aim to find out the water content required to produce a cement paste of standard consistency as specified by the IS: 4031 (part4)

Standard consistency of cement is 35%

5.1.4 SPECIFIC GRAVITY OF FINE AGGREGATE Specific gravity of fine aggregate is calculated as 2.65

5.1.5 SPECIFIC GRAVITY OF COURSE AGGREGATE Specific gravity of coarse aggregate is calculated as