Which is a mechanical cause of concrete deterioration?

Overloading, impact, vibration/fatigue, settlement, earthquakes, explosion

What control applies to mechanical deterioration?

Correct design for loads, joints, stiff foundations, and hard aggregate and high strength for wearing surfaces

How does freezing and thawing damage concrete?

Water in pores expands about 9% on freezing, creating hydraulic pressure; repeated cycles crack and scale it

Ice contracts and pulls the paste apart

Frozen water reacts with C3A to form ettringite

Freezing dissolves Ca(OH)2 which leaches out

Why does drying shrinkage cause cracks?

Shrinkage is restrained by steel or supports, producing tensile stress; the cracks let aggressive agents in

Concrete expands on drying and crushes

Shrinkage only occurs when concrete freezes

Shrinkage is caused by sulphates

Asked 6/32
2075 Ashwin · 4+3 marks

Mechanical and physical causes of deterioration

Short answer

Mechanical causes include overloading, impact, vibration, settlement, and abrasion. Physical causes are freeze-thaw cycles, thermal effects, drying shrinkage, salt crystallization, and wetting/drying, all of which increase permeability and accelerate chemical attack.

Describe the mechanical and physical causes of concrete deterioration.

Mechanical causes

Mechanical causes are those from applied loads and impacts:

Overloading and structural defects, causing cracks beyond design level.
Impact (vehicle collision, pile driving, falling objects), vibration and fatigue from machinery or traffic, causing cracks and spalling.
Settlement and movement of supports, and earthquakes.
Abrasion and erosion by traffic, water flow with silt and cavitation, which wear the surface.
Explosion, blasting.

Control: correct design for loads, joints, stiff foundations, hard aggregate and high strength for wearing surfaces.

Physical causes

Cause	Mechanism	Effect and control
Freezing and thawing	Water in pores freezes, expanding by 9%, causing hydraulic pressure; repeated cycles	Scaling, cracking, D-cracking. Use air entrainment (4 to 7%), low w/c, sound aggregate
Thermal effects (temperature cycle, fire)	Differential expansion/contraction; above 300 °C paste loses water, above 500 °C Ca(OH)2 decomposes	Cracking, spalling, loss of strength. Joints, cover, insulation
Shrinkage and moisture movement	Drying shrinkage restrained by steel/supports	Cracks, which open the way for aggressive agents. Low w/c, curing, joints
Abrasion	Wear by traffic, sliding or rolling	Surface loss in pavements, floors. Hard aggregates, high strength, surface treatments
Erosion and cavitation	High velocity water with silt, or vapour bubbles collapsing	Pitting of spillways. Smooth surface, high-strength concrete
Salt crystallisation	Salt solution crystallises in pores on drying	Pressure causing scaling and efflorescence. Dense concrete, membranes
Wetting and drying	Moisture gradients cause cyclic stress	Cracking and surface deterioration

All physical processes increase permeability and speed up chemical attack, so low w/c, good curing and compaction help in all of them.

✓ Answer checked by Claude Sonnet 5.5

Physical causes of concrete deterioration · Concrete Technology and Masonry Structure, chapter 6 · asked 6×
Physical and chemical causes of deterioration · Concrete Technology and Masonry Structure, chapter 6 · asked 5×
Chemical causes of concrete deterioration · Concrete Technology and Masonry Structure, chapter 6 · asked 5×
Causes of deterioration; effects of steel corrosion · Concrete Technology and Masonry Structure, chapter 6 · asked 2×
Physical properties of OPC and concrete behaviour · Concrete Technology and Masonry Structure, chapter 1
Causes of deterioration of stone · Civil Engineering Materials, chapter 2 · asked 4×
Physical and mechanical properties of wood · Civil Engineering Materials, chapter 7

All Concrete Technology and Masonry Structure chapter 6 questions →

Mechanical and physical causes of deterioration

Mechanical causes

Physical causes

Related questions