In this article we will discuss about:- 1. Meaning of Aggregates 2. Classification of Aggregates 3. Deleterious Substance 4. Soundness 5. Thermal Properties 6. Sieve Analysis 7. Fineness Modulus 8. Maximum Size 9. Handling. Meaning of Aggregates: Originally mineral aggregate was used as inert filler in the cement concrete. In fact the aggregate is not inert filler and its physical, [...]
In addition to the petro-logical (rock structure etc.) character of aggregate, its external characteristics also are of importance which have marked influence on the properties of concrete. Following characteristics are of importance: 1. Shape and texture of particle. 2. Crushing strength of aggregate. 1. Shape of Particles: The shape of the particles depends upon the source of aggregate. The different [...]
Till 1940, aggregates were considered as inert materials, but after 1940, it has been clearly established that aggregates are not fully inert. Some of the aggregates contain reactive silica which reacts with the alkalis (Sodium oxide Na2O and potassium oxide K2O) present in cement. For the first time in U.S.A. it was observed that many failures of concrete structures as [...]
Several mechanical properties of aggregate are of interest for the manufacture of concrete, specially high strength concrete subjected to high wear. Some of them are discussed here in brief: 1. Toughness 2. Hardness 3. Specific Gravity 4. Porosity of Aggregate 5. Bulking of Sand. Property # 1. Toughness: It is defined as the resistance of aggregate to failure by impact. [...]
In this article we will discuss about:- 1. Introduction to Practical Grading of Aggregates 2. Grading of Fine and Coarse Aggregates 3. Grading. Introduction to Practical Grading of Aggregates: The grading should be such that it could give a reasonable workability with minimum segregation. Segregation is very important in the production of good concrete. A workable mixture which could produce [...]
Factors that affect the grading of aggregate are: 1. Surface Area of the Aggregate 2. Relative Volume Occupied by the Aggregate 3. Workability of the Mix 4. Segregation. Factor # 1. Surface Area of the Aggregate: For a given maximum size of aggregate, larger the size of aggregate particles, lesser the surface area of aggregate in a given mix, which [...]
In this article we will discuss about the natural and artificial types of light weight aggregates. 1. Natural Aggregate: They are not of uniform quality, and not found in many countries. As such they are not used universally for making light weight concrete. Out of all the natural light weight aggregate, only pumice is used widely. This is further classified [...]