In this article we will discuss about grading requirements of fine aggregates; the parameter that every civil engineer must know. As we all know, the global village of construction industry has evolved promptly with diverse range from smallest building structures to skyscrapers in recent past, all around. This all mesmerizing development is grooming around the most widely used construction material i.e. Concrete.
Concrete is a hard mass composed of fine and coarse aggregate bonded together with cement that hardens over time. Therefore, to work with concrete in the construction industry, it is intensely imperative to understand the requisite properties of its constituents.
In this article, we will be fostering the most important specification (grading) of fine aggregates: a fundamental integral of concrete.
What is grading of Fine Aggregates
Fine aggregates, one of the principal constituents of concrete, are generally natural sand or crushed stone particles that pass through 4.75mm sieve (Sieve#4).
The grading which is also known as sieve analysis is simply an exploration of particle size distribution and represented as % passing from each sieve of fine aggregate.
Therefore, to examine the grading of fine aggregates, the common procedure of sieve analysis shall be adopted.
Significance of Fine aggregates grading
The particle size distribution/grading of fine aggregates (sand) substantially governs the mix properties of concrete such as workability, bond development and integrity of resulted mass which are of prime importance in the ambit of construction industry.
Therefore, it is of the need for every Civil Engineer to understand the basic grading requirements to optimize the concrete properties which otherwise may ruffle the workability, pumping, placing and finishing of the concrete mix.
Grading Requirements Table
American Society for Testing and Materials (ASTM) an international standards organization, in ASTM C33, specifies the percent passing limits for each sieve of fine aggregates.
Those specified limits are listed in the table given below:
|S.N.||Sieve #||Sieve Size||Percent Passing|
These specified limits have been stated in Table-1 of ASTM C33.
It is preferable to have fine aggregates withe % passing in the average zone of each sieve limit rather to be nearer on the extreme ends which will definitely produce a concrete mix of fitting workability.
About the Author:
Umair Ashraf is a professional Civil Engineer who has been working with a globally renowned organization on various construction projects of international recognition since last four years. Enriched with this vast experience in Civil Engineering as well as construction industry, he is going to facilitate the learners in their technical skills development through his articles based on international standards.