Concrete Repair Materials and Selection Criteria

Ali H. Al-Gadhib

by

Civil Engineering DepartmentKFUPM

Presentation Flow

• Concept of Load / Capacity Envelope

• Dimensional Incompatibility Behavior

• The Specialist Formulator

• Total Package Solution

• Concrete Repair Systems

• Criteria for Selection of Repair Materials

• Conclusions

The Specialist Formulator

Is one who employs materials scientists and chemists to take basic materials from the petrochemicals, plastics, cement, aggregate, and other related industries and tailor them into useful repair materials which can be applied in as simple a manner as possible on site.

INVESTMENT ON R&D

Company I

4% of the total annual turnover

=

Company II

4% of the total annual turnover

=

Result of 46 Repair Material

Ten

sile

Str

ess

Time

Tensile stress relief throughtensile creep

Elements of a cementitious ‘repair package’

Typical PropertiesTypical PropertiesFor Acrylic Reinforced Cementitious, Flexible

Waterproof Coating

(1) The shrinkage compensation agent is included to

counteract the natural phenomenon of contraction

due to low of moisture. These agent have two

distinct mechanism to wok at plastic.

(2) Silica fume is to impart dense matrix and enhance

water tightness or wall is increase strength.

(3) Polymer is added in powder form to increase

flexibility, adhesion, and water tightness.

(4) Microfibers to impart flowability and badge cracks.

(5) Pulverized superplasticers to increase workability

after a low which ratio.

Polymer Modified CementatiousRepair Mortar

• Modified cementations• Polymer modified cementations• Polymer fiber modified cementations• Epoxy – base resin• Epoxy – cementations repair• Crack injection• Micro concrete• Corrosion inhibitors• Protective systems• External strengthening

Reinforced Concrete Repairand it Protection Systems

Compressive strength (N/mm2) 55-110

Compressive modulus (kN/mm2) Flexural strength (N/mm2) 25-30

Elongation at break (%) 8-17

Linear coefficient of thermal expansion per oCWater absorption, 7 days at 25o C (5)Maximum service temperature under load (o C)

Rate of development of strength at 20o C

Polyester resin groutsmortars and concretes,

25-35 10 6

50-80

2-6 hours

Polymer modifiedcementitious systems

10-80

6-152-8

8-20 10 6

100-300

1-7 days

Physical Properties ofRepair Materials

Companies of Concrete Repair

1) Degussa Company www.degussa.com

2) Sika Company

www.sika.com

3) Fosroc Company

www.fosroc.com

Indices for Durable Repair

• Repair Diffusivity• Free Drying Shrinkage• Free Specific Tensile Creep• Repair Tensile Strength• Tensile Modulus of Elasticity

No matter how superior the

repair material system,

it can not go beyond and bypass

the quality of workmanship