Now more and more buildings will be strengthened for various reasons. Shanghai Horse Construction has been in strengthening material for many years, and the following reasons are summarized.

Material 

1. unqualified cement quality or improper selection

(1) the excessive hydration heat causes the temperature stress, which causes the cracking of the concrete.

(2) the alkali content is too large in the expansion of aggregate reaction expansion

2. poor quality of sand and stone

(1) high mud amount and lack of strength

(2) high sand salt caused by steel corrosion

Design 

Insufficient safety and insufficient estimation of environmental effects

(1) over the design load cause structural cracking or deformation

(2) variable load lead problem, such as a load of snow, a load of dust.

(3) errors in the design

Usage

1. use after a certain period, due to technological innovation, to increase the load or expand the column, change the use of functions

2. floods, storms, fires and earthquakes and other disasters, the use of structural destruction

3. inhomogeneous settlement of foundation

4. seismic reinforcement of existing buildings

Construction 

1. inaccurate ingredients, unevenly stirred

(1) insufficient strength of concrete

(2) poor homogeneity

2. irrigating unreal or too long interval for construction seam

(1) concrete non compacting, honeycomb, hole

(2) water seepage along the construction seam

3. poor maintenance

(1) poor early curing, dry or surface loss of water

(2) early freezing

4. reinforcement deviation

(1) the improper position of the steel bar and the decrease of the bearing capacity

(2) insufficient protection

5. template deformed or leaking

(1) component surface pits

(2) inaccurate structure size

Environmental 

1. freezing and thawing cycle

Frost damage (surface cracking or damage)

2. corrosion medium

(1) concrete corrosion

(2) corrosion of steel bar

3. carbonization, sea water and sea breeze

Corrosion of steel bar