Concrete in Brief
Properties of concrete
Easily mixed, handled, transported, placed in position and compacted
Segregation Separation of constituent materials of concrete Creates larger voids and reduces the durability and strength. Bleeding Water from concrete comes out of the surface Produces pores in concrete and reduces strength. Strength Compressive strength, tensile strength, flexural strength. Elasticity Concrete not an elastic material Stress in concrete a strains in initial stages Influenced by elastic properties of aggregate, mix proportion, age of concrete, type of cement. Shrinkage Change in volume of concrete due to loss of moisture at different stages.
Affects strength and durability
Leads to the formation of cracks
Depends on constituents of concrete, size of member, amount of water present in concrete and environmental conditions
Gradual increase in strain without increase in stress, with time. Depends on stress in concrete, age at loading and duration of loading
Ability to resist weathering action, chemical attack, abrasion or any other process of deterioration.
Factors affecting are environment, cover to embedded steel, type and quality of constituent materials, cement content and water cement ratio, workmanship to obtain full compaction, efficient curing and shape and size of member
Types of concrete
Shotcrete is a process where concrete is projected or “shot” under pressure using a feeder or “gun” onto a surface to form structural shapes including walls, floors, and roofs.
Shotcrete has high strength, durability, low permeability, excellent bond and limitless shape possibilities.