T4-x3: Standards for Concrete Repair Flashcards
(27 cards)
What is the standard for concrete repair?
BS EN 1504
What does BS EN 1504 specify?
- Minimum performance levels
- Identification tests
- Guidance on site application
What are the different causes of deterioration in BS EN 1504-9
What are the seven steps of EN 1504-9: 2008
- Assess damage
- Management strategy options
- Factors affecting management strategy
- Choose repair principles
- Choose method(s)
- Choose materials
- Specify ongoing requirements
What are the 11 principles of EN 1504-9:2008
- Protect against ingress
- Moisture control
- Concrete restoration
- Structural strengthening
- Increasing physical resistance
- Resistance to chemicals
- Preserving or restoring passivity
- Increasing resistivity
- Cathodic control
- Cathodic protection
- Control of anodic areas
What property does a bonding agent promote?
Promote adhesion
What does the stiffening time tell us?
When workability is lost
What does capillary absorption need to have?
The ability to absorb surface water
High-flow mortar needs extermely high flow. What does it need to avoid?
Have extremely high flow without bleeding or segregation
What are different types of identification tests?
- Compressive strength
- Density
- Stiffening time
- Workability (flow of mortar/ concrete)
- Infrared analysis
What are three main applications of surface protection systems for concrete?
- Improve acid/chemical resistance
- Reduce chloride ingress (e.g. seal surface against chloride-bearing water)
- Reduce carbonation rate
(e.g. partial barrier to CO2, prevent neutralisation of the high pH cement paste)
What are four good things about the application SPS?
- Tolerant to poor surface preparation
- Tolerant to moisture on application, and during core
- Resistant to to alkaline surface conditions
- Low flammability
What are the two main benefits of SPS?
They are durable
- under strong radiation
- rain/wind/temp/freeze-thaw cycles
Low-Cost
- special application requirements
- ease of re-coating
What are three types of coating?
Hydrophobic impregnation:
- produces a water-repellent surface
Impregnation (image):
- reduces surface porosity and strengthened surface
- pores and capillaries filled
Coating:
- continuous protective layer on surface
Name two types of binder
- Cement-based
- Epoxy resin
[NAQ] applications for SPS
[NAQ] anti-carbonation performance of SPS
What formula is used for the anti-carbonation performance of SPS?
R = ut
NB. won’t be asked to do this type of calc in exam
[NAQ] example calc for anti-carbonation performance of SPS (for a target R-value)
NB. won’t be asked to do this type of calc in exam
What are the two purposes of anti-carbonation paint?
- Protection
- Aesthetics
What is a type of SPS?
Crack bridging paints/ membranes
What are two types of structural bonding products and systems?
- Steel plate
- Carbon and other fibre
What are bonded plate reinforcements?
The bonding of external plates (of steel/fibre-reinforced composites) to the surface of a concrete structure for strengthening
What is bonded mortar or concrete
The bonding of hardened concrete to hardened concrete
- typically associated with the use of precast units in repair and strengthening
- uses an adhesive bonded joint
