ASTM C142ASTM C142ASTM C142Stone aggregate is a fundamental raw material for all countries. However, the testing and specification of aggregate is often overlooked or not considered. This has serious implications for the life and maintenance of buildings and infrastructure which can cost a lot of money in the future to repair or replace and at worst lead to structural failure and risk to human lives.


Introduction:

The construction aggregates sector is an important part of most modern developed economies. Aggregates account for approximately 85% of the non-energy minerals extracted. They are essential for constructing and maintaining what is literally the physical framework of the buildings and infrastructure. To ensure that construction aggregates are fit for purpose and meet the requirements of the endues it is important to have an understanding of the geology of the resources, production processes, and standards and test methods used to evaluate their suitability. Construction aggregate is normally defined as being hard, granular materials which are suitable for use either on their own or with the addition of cement, lime or a bituminous binder in construction. Important applications include concrete, mortar, road stone, asphalt, railway ballast, drainage courses and bulk fill. There are three main types: natural aggregate (from mineral sources with nothing more than physical processing, often referred to as ‘primary aggregate’), manufactured aggregate (derived from industrial processes as a by-product, often referred to as ‘secondary aggregate’) and recycled aggregate (recovered from material previously used in construction) (BGS, 2013). This paper will focus on natural (primary) aggregate.

STANDARDS AND TEST METHODS

The testing of construction aggregate is carried out to international standards. The quality of quarry products used in the UK is controlled by the European Standards for Aggregates for concrete, mortar, asphalt and road construction. The key parameters for aggregates are particle size and shape, physical and mechanical properties and durability. The laboratory evaluation of construction aggregate ranges from simple and low cost to sophisticated and expensive testing.

S No Type of Test / Parameters Test Method Max Limit
1
2
3
4
5
6
7
8
9
Size Analysis (10-20)
Clay lumps & Friable Particles %
water Absorption (SSD)%
Specific Gravity (Particle Density)
One or more Fracture Faces, %
Flakiness Index, %
Elongation Index, %
Los Angeles Abrasion, %
Aggregates Crushing Value,%
ASTM C142
ASTM C127
ASTM C127
ASTM D5821
BS EN 933-3
BS EN 933-4
ASTM C131
BS EN 1097-2
30, 70 %
2% Max
2% Max
2.60 (min)
100 Max
30 Max
25 Max
30 Max
25 Max

 

Category Unit Weight of Gryrodded Aggregate(kg/m3) Unit Weight of Concrete(kg/m3) Typical Concrete Strengths(MPa) Typical
Applications
Ultra lightweight
Lightweight
Structural
Lightweight
Normal
Heavy weight
<500
500-800
650-11001100-1750>
2100
300-1100
1100-1600
1450-19002100-2500
2900-6100
<7
7-14
17-3520-40
20-40
Nonstructural
insulating material
Masonry units structural
structural
Radiation
shielding

 


Stone Aggregate Stone Aggregate Stone Aggregate Stone Aggregate