WHAT IS SURFACE INDEX OF AGGREGATES?

Surface Index of Aggregates Surface index of aggregates is another way to represent the specific surface of aggregate. This method was suggested by Murdock.  Murdock provided some empirical numbers to represent the specific surface of different aggregates grading (as shown in the table below). Surface Index Values for Different Aggregate Grading Sieve Size Within Which … Read more

20+ DIFFERENT TYPES CEMENTS AVAILABLE IN INDIA AND CORRESPONDING IS STANDARDS

Cement Bag

Types Of Cement and Respective Indian Standards SlNo Types Of Cement Reference Indian Standard 1 Ordinary Portland Cement 33 Grade IS:269 2 Ordinary Portland Cement 43 Grade IS:8112 3 Ordinary Portland Cement 53 Grade IS:12269 4 Rapid Hardening Cement IS:8041 5 Extra Rapid Hardening Cement — 6 Sulphate Resisting Cement IS:12330 7 Portland Slag Cement … Read more

WHAT IS SPECIFIC SURFACE OF AGGREGATE AND IT’S IMPORTANCE

Specific Surface of Aggregate The surface area per unit weight of the material is termed as specific surface. This is an indirect measure of the aggregate grading. Specific surface increases with the reduction in the size of aggregate particle. The specific surface area of the fine aggregate is very much more than that of coarse … Read more

WHETHER THE ANGULAR AGGREGATE OR ROUNDED AGGREGATE WILL MAKE BETTER CONCRETE?

Which One Is Better For Concrete-Rounded or Angular Aggregate Angular aggregate are superior to rounded aggregate from the following two points of view. Angular aggregate exhibit a better interlocking effect in concrete, which property makes it superior in concrete used for roads and pavements. The total surface area of rough textured angular aggregate is more … Read more

FLOW TABLE TEST TO MEASURE FLOW VALUE OF CONCRETE

Objective To measure flow value of concrete using flow table apparatus Equipment Flow table Slump cone shaped mould Wooden tamping bar   Procedure Place the flow table on a leveled surface Clean the top of the table and inner surface of the mould using a damp cloth. Place the slump cone centrally on the table. … Read more

WHAT IS ANGULARITY NUMBER OF AGGREGATE?

Angularity Number Angularity number is used to give an indication of shape of aggregate. The concept of angularity number was suggested by Shergold. It gives a qualitative representation of shape of aggregate. Angularity Number Test Angularity number test gives an idea of how angular the aggregate is. This is based on the percentage of voids … Read more

HOW TO DETERMINE STANDARD CONSISTENCY OF CEMENT PASTE?

Test Standard Reference IS:4031(Part 4):1988-Methods of physical tests for hydraulic cement (Determination of consistency of standard cement paste) Overview Standard consistency of a cement paste is defined as that consistency which will permit a vicat plunger having 10 mm dia and 50 mm length to penetrate to a depth of 33-35 mm from top of … Read more

HOW TO PREVENT DAMAGE TO FRESHLY LAID CONCRETE?

Prevention to Damage Freshly laid concrete is liable to damage due to heavy impacts. In order to prevent damage: Floors should be covered in order to avoid surface damage Projecting ornamental members should be protected against falling material. Projecting reinforcing bars should not be used for climbing or subjected to severe usage. Stripping of forms … Read more

WHEN TO REMOVE FORMWORK FOR DIFFERENT CONCRTE WORKS?

In normal circumstances (generally where temperature are above 200C), and where ordinary cement is use, forms may be struck after expiry of following periods: Walls, columns and vertical sides of beams 24 to 48 hours as may be decided by the engineer in charge Slabs (props left under) 3 days Beam soffits (props left under) … Read more

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF PRECAST CONCRETE?

Precast Concrete

Advantages of Precast Concrete Following are the advantages of precast concrete: The concrete of superior quality is produced as it is possible to have better technical control on the production of concrete in factory. It is not necessary to provide joints in the precast construction. The labour required in the manufacturing process of the precast … Read more