Concrete is produced using a varied selection of constituent materials brought together to form a semi-homogeneous solid. The types of concrete available is either based on the compression strength or a reflection of its final application.
Using only specified aggregates according to current local and international standards, GRM takes extreme care in the selection of aggregate properties. Characteristics that are considered include:
• Strength (crushing impact and abrasion values)
• Particle shape and surface texture
• Relative density and water absorption
Although concrete is sometimes viewed as a single material, it can be produced with many variable characteristics including strength, fluidity, colour and weight. Concrete, in the plastic state, is known as the ‘green concrete’ and when it has become a hard mass, is known as hardened concrete or normal concrete.
Properties Of Green Concrete
• Workability, which constitutes the ease with which concrete can be compacted fully without segregating or bleeding.
• Segregation, which is separation of coarse particles within the green concrete.
• Bleeding, which is the appearance of water along with cement particles on the surface of freshly laid concrete.
• Harshness, which is the resistance offered by the concrete to its surface finish.
• The properties of hardened concrete include compressive, flexural and tensile strengths, dimensional change, durability and impermeability.
• GRM produce a wide range of concrete mixes that conforms to an industry norm density of between 1,200-2,600 kg/m3.
The durability of concrete may be defined as the ability of concrete to resist weathering action, chemical attack and abrasion while maintaining its desired engineering properties. Different concretes require different degrees of durability depending on the exposure environment and properties desired. For example, concrete exposed to tidal seawater will have different requirements to that of an indoor concrete floor. The ultimate durability and life of concrete depends on the concrete ingredients themselves, their proportioning, interactions between them, placing and curing practices and
the service environment.
Read the full article on the latest Hub magazine, The Knowledge Issue.