Inspection Flashcards

1
Q

What is the purpose of a RICS Home survey?

A

The surveyor who provides the RICS Home Survey service aims to give the client professional advice to:
- make an informed decision on whether to go ahead with buying the property
- consider what further advice they should take before committing to purchasing the property.
- The nature and content of the report will vary between the different levels of service.

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2
Q

What framework is available and should be followed by RICS members/firms for home surveys?

A

The Home survey standard, 1st edition.

This professional standard sets out a series of concise mandatory requirements.

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3
Q

What is the content of a level one home survey?

A

For each element of the building, the RICS member should:
- Identify and describe each part or element of the building so it can be identified by the client and describe its condition. The description should be clear and concise expression of the RICS member’s professional assessment of each part or element.

This assessment should help the client gain an objective view of the condition of the property, make a decision and, once in ownership (if the client is a buyer), establish appropriate repair/improvement priorities. A condition rating system (number and RAG) is one way of achieving this, although RICS members may use their own prioritisation methodology. Whatever the choice, any system must be clearly defined in the information given to the client. The RICS Home Survey – Level 1 does not include advice on repairs or ongoing maintenance and it does not include a valuation.

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4
Q

What is the content of a level three home survey?

A

A level three service should reflect the thoroughness and detail of the investigation. It should address the following matters:

  • the form of construction and materials used for each part of the building should be described in detail, outlining any performance characteristics. This is especially important for older and historic buildings where the movement of moisture through building materials can be critical to how the building performs
  • obvious defects should be described and the identifiable risk of those that may be hidden should be stated
  • remedial options should be outlined along with, if considered to be serious, the likely consequences if the repairs are not done
  • a timescale for the necessary work should be proposed, including (where appropriate and necessary) recommendations for further investigation
  • future maintenance of the property should be discussed, identifying those elements that may result in more frequent and/or more costly maintenance and repairs than would normally be expected
  • the nature of risks of the parts that have not been inspected should be identified and
  • prioritisation of issues should be outlined.
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5
Q

What is the content of a level two home survey?

A

A survey level two service should follow a similar structure and format to level one. Although it will provide more information, it should still be short and to the point, avoiding irrelevant or unhelpful details and jargon. Material defects should be described and the identifiable risk of those that may be hidden should be stated. A level two report will have the following additional characteristics:

  • it should include comments where the design or materials used in the construction of a building element may result in more frequent and/or more costly maintenance and repairs than would normally be expected
  • the likely remedial work should be broadly outlined and what needs to be done by whom and by when should be identified
  • concise explanations of the implications of not addressing the identified problems should be given and
  • cross-references to the RICS member’s overall assessment should be included.

Survey level two reports should also make it clear that the client should obtain any further advice and quotations recommended by the RICS member before they enter into a legal commitment.

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6
Q

Do home surveys comment on energy matters / EPC’s?

A

At all levels of service RICS members and regulated firms must be able to identify and advise on defects and deficiencies caused by inappropriate energy efficiency measures implemented at the subject property.

In addition, the different levels should include the following particular features:

  • Level 1 – where the EPC has not been made available by others, the RICS member should obtain the most recent certificate from the appropriate central registry where practicable. The relevant energy and environmental rating should be reviewed and stated.
  • Level 2 – in addition to that described for level 1, checks should be made for any obvious discrepancies between the EPC and the subject property and the implications explained to the client.
  • Level 3 – in addition to that described for levels 1 and 2, at this level the RICS member should give advice on the appropriateness of any energy improvements recommended by the EPC and other comments on energy efficiency.

Members/firms may wish to offer more additional energy services and these must be reflected in the terms and conditions.

Where additional energy services are offered for older and/or complex properties, historic buildings and those in a neglected condition, RICS members must have the level of competence and technical knowledge to deliver them.

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7
Q

What is a level one survey?

A

This service is designed for clients (buyers, sellers and owners) seeking a professional and objective report on the condition of the property at an economic price. As a result, it is less comprehensive than survey level two and survey level three.

Less extensive visual inspection than for the other survey levels.
No tests of the building fabric or services are undertaken.
Describes the condition of the building, its services and the grounds.
It highlights relevant legal issues and any obvious risks to the building, people or grounds.
The report is succinct and provides an assessment of the relative importance of the defects and problems. Where the surveyor is unable to reach a conclusion with reasonable confidence, a recommendation for further investigation should be made.

Does not include advice on repairs or ongoing maintenance and this, combined with the less extensive inspection, usually means it is better suited to conventionally built, modern dwellings in satisfactory condition. It will not suit older or complex properties, or those in a neglected condition.

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8
Q

Why choose a level one survey?

A

Choose this report if you’re buying or selling a conventional house, flat or bungalow built from common building materials and in reasonable condition. This service includes:

  • a visual inspection that is less comprehensive than the level 2 or 3.
  • clear ‘traffic light’ ratings of the condition of different parts of the building, services, and the grounds, showing problems that may require varying degrees
    of attention
  • a summary of risks to the building, people and grounds and.
  • an assessment of the relative importance of the defects and problems.

No tests of the building fabric or services are undertaken.

Does not include advice on repairs or ongoing maintenance and it does not include a valuation.

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9
Q

What is a level two survey?

A

This level of service is for clients who are seeking a professional opinion at an economic
price. It is, therefore, less comprehensive than a level three service. The focus is on assessing
the general condition of the main elements of a property.

This intermediate level of service includes a more extensive visual inspection of the building, its services and grounds, but still without tests.

Concealed areas normally opened or used by the occupiers are inspected if it is safe to do so (typical examples include roof spaces, basements and cellars).

The report objectively describes the condition of the different elements and provides an assessment of the relative importance of the defects/problems.

Although it is concise, the report does include advice about repairs and any ongoing maintenance issues.

Where the surveyor is unable to reach a conclusion with reasonable confidence, a recommendation for further investigations should be made.

This level of service suits a broader range of conventionally built properties, although the
age and type will depend on the knowledge and experience of the RICS member. This level of
service is unlikely to suit:

  • complex buildings, for example those that have been extensively extended and altered
  • unique or older historic properties – although survey level two services may be appropriate for some older buildings, the decision will depend on the RICS member’s proven competence and knowledge and the nature of the building itself. For example, a survey level two report on homes with traditional timber frames or those built much before 1850 is likely to be inconclusive and be of little use to the client or
  • properties in neglected condition.

In such cases, a survey level two service will often result in numerous referrals for further investigations, an outcome that many clients find disappointing. Where the client is planning to carry out extensive repair and refurbishment work in the future, the RICS member should give advice on suitable additional services.

An option including a valuation is available this will include;
- the surveyor’s professional opinion on the ‘market value’ of the property
- an insurance reinstatement figure for the property
- a list of problems that the surveyor considers may affect the value of the property.

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10
Q

What is a RICS Home Survey Level three survey?

A

This level of service is for clients who are seeking a professional opinion based on a detailed assessment of the property.

The service consists of a detailed visual inspection of the building, its services and the grounds and is more extensive than a survey level two. Concealed areas normally opened or used by the occupiers are inspected if it is safe to do so (typical examples include roof spaces, basements and cellars).

Although the services are not tested, they are observed in normal operation – in other words, they are switched on or off and/or operated where the
occupier has given permission and it is safe to do so.

The report objectively describes the form of construction and materials used for different parts of the property. It describes the condition and provides an assessment of the relative importance of the defects/problems.

Additionally, it should:
- describe the identifiable risk of potential or hidden defects in areas not inspected
- propose the most probable cause(s) of the defects based on the inspection
- outline the likely scope of any appropriate remedial work and explain the likely consequences of non-repair
- make general recommendations in respect of the priority and likely timescale for necessary work and
- give an indication of likely costs (this aspect would not normally form part of the level three service, but some RICS members may choose to include it). Where costings are included, this must be reflected in the terms and conditions.

Where an RICS member feels unable to reach the necessary conclusions with reasonable confidence, they should refer the matter for further investigations. However, at survey level three such referrals should be the exception rather than the rule. A survey level three report should aim to provide the client with all the information they need to make a decision. This level of service will suit any domestic residential property in any condition depending on the competence and experience of the RICS member.

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11
Q

Why choose a level 2 survey?

A

Choose this report if you need more extensive information whilst buying or selling a conventional house, flat or bungalow, built from common building materials and in reasonable condition.

The focus is on assessing the general condition of the main elements of a property. This intermediate level of service includes a more extensive visual inspection of the building, its services and grounds, but still without tests.

Concealed areas normally opened or used by the occupiers are inspected if it is safe to do so (typical examples include roof spaces, basements and cellars). The report objectively describes the condition of the different elements and provides an assessment of the relative importance of the defects/problems.

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12
Q

Why choose a Level 3 survey?

A

Choose this report if dealing with a large, older or run-down property, a building that is unusual or altered, or if you’re planning major works. It costs more than the other RICS reports because it gives detailed information about the structure and fabric of the property. This service includes:
- a detailed visual inspection of the building, its services and the grounds and is more extensive than a survey level two
- Concealed areas normally opened or used by the occupiers are inspected if it is safe to do so (typical examples include roof spaces, basements and cellars)
- Although the services are not tested, they are observed in normal operation – in other words, they are switched on or off and/or operated where the occupier has given permission and it is safe to do so.

The report objectively describes the form of construction and materials used for different parts of the property. It describes the condition and provides an assessment of the relative importance of the defects/problems.

Additionally, it should:
- describe the identifiable risk of potential or hidden defects in areas not inspected
- propose the most probable cause(s) of the defects based on the inspection
- outline the likely scope of any appropriate remedial work and explain the likely consequences of non repair; and
- make general recommendations in respect of the priority and likely timescale for necessary work.

The surveyor may also be able to provide an estimate of costs for identified repairs if agreed with you in advance.

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13
Q

What are the condition ratings in the rics home survey reports?

A
  • Condition rating 3 – Defects that are serious and/or need to be repaired, replaced or investigated urgently. Failure to do so could risk serious safety issues or severe long-term damage to your property. Written quotations for repairs should be obtained prior to legal commitment to purchase.
  • Condition rating 2 – Defects that need repairing or replacing but are not considered to be either serious or urgent. The property must be maintained in
    the normal way.
  • Condition rating 1 – No repair is currently needed. The property must be maintained in the normal way.
  • NI – Elements not inspected.
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14
Q

What are some criticisms of rics home survey reports?

A

Generally only a visual inspection. This means that we do not take up carpets, floor coverings or floorboards, move furniture or remove the contents of cupboards. Also, we do not remove secured panels or undo electrical fittings.

Roofs, chimneys and other surfaces on the outside of the building are inspected from ground level and, if necessary, from neighbouring public property and with the help of binoculars.

Generally do not report on the cost of any work to put right defects or make recommendations on how these repairs should be carried out.

No great depth as only broken broadly down by element.

The report contains multiple caveats and exclusions in order to cover the surveyor should anything unseen be missed.

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15
Q

What is a Reinstatement cost assessment?

A

If damage is done to the building the cost of knocking it down and rebuilding it (Net rebuild costs). The cost includes; demolition and debris removal, rebuild costs, professional and statutory fees, additional costs to comply with current regs, any tenant alterations, external works e.g. utilities supply.

Generally, all assessments are made on the basis of total loss or of such substantial damage that the entire building will require demolition and rebuilding.

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16
Q

What does a reinstatement cost assessment report include?

A

Description of the property
- Specific exclusions
- Reinstatement costs
- Reinstatement period
- Elemental break down includes; element, description, rate, IPMS 2, Cost & Notes

RICS professional standard on Reinstatement cost assessment of buildings 3rd edition 2018 identifies
- the manner in which assessments should be approached
- the nature and extent of the information to be collated and
- the manner in which this information should be processed and the assessment calculated
and submitted.

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17
Q

What are the types of cost reinstatement assessment?

A
  1. Day one reinstatement
  2. Reinstatement including inflation provision
  3. Reinstatement less wear and tear (indemnity basis)
  4. Obsolete buildings
  5. Site clearance, debris removal and ‘making safe’
  6. Second-hand value of building materials
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18
Q

What is Day one cost reinstatement assessment?

A

Day one reinstatement - How most UK buildings are insured “new for old basis”. Known as declared Value - Cost of rebuilding on associated costs without inflation.

The declared value figure should be the equivalent of a fixed price, lump sum, competitive
tender submitted by a suitable and competent contractor for works to commence on site
on the first day of the period of insurance, together with appropriate allowances for demolition and other costs and all associated professional and
other statutory fees.

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19
Q

What is Reinstatement including inflation provision?

A

Reinstatement including inflation provision - Two separate parts to the policy, one sum is the declared value one allowance for inflation. Insurers accept a margin of error of 15% at the time of loss

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20
Q

What is Reinstatement less wear and tear (indemnity basis)?

A

Few buildings are insured on this basis of indemnity. Reduced value due to old age or poor condition upon assessment. Elements that have not useful life left will be valued at £0

When a building is very old or not in a good state of repair, the insurer may be unwilling to grant full
reinstatement cover or the insured may wish to save premium by having a lower sum insured
while accepting that there would be significant and inevitable betterment contribution to be
made in the event of repairs being necessary.

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21
Q

What is Obsolete building reinstatement assessment?

A

This rare basis of assessment could be suitable if a building would be demolished and rebuilt in a different and cheaper form if it was destroyed or seriously damaged. Partial damage would be repaired up to an agreed amount but beyond that amount the building would be knocked down and replaced by a modern building providing the same function. The premium would be calculated on the full cost of reinstatement of the existing building with a reduction to reflect that the insurers’ limit of liability is a lesser amount based on the demolition of what remains of the original building and the cost of the modern replacement. The saving in premium is relatively small as most losses are partial and the insurers would only save on larger claims.

This basis is particularly useful for both insured and insurer where the ‘obsolete’ building is a poor risk carrying a high premium. The insured saves on premium and the insurer has a lower exposure. Surveyors may be asked to assess the full reinstatement cost, as existing, and the comparable cost of the provision of a replacement with the same functionality to the client, which could be a different shape, or a more efficient or cost-effective design, e.g.
clear span portal frames in lieu of a cumbersome and costly north light roof with many
intermediate columns.

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22
Q

What is Site clearance, debris removal and ‘making safe’ reinstatement assessment?

A

Site clearance, debris removal and ‘making safe’ costs only - Buildings due for demolition, if damage occurs it can be brought forward. If demolition costs increase due to damage it is to be made safe.

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23
Q

What is Second-hand value of building materials reinstatement assessment?

A

Second-hand value of building materials - The value of items if they were sold on second hand. e.g. fireplace, roof tiles. Very rarely used.

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24
Q

What equipment is required for an inspection?

A

Mobile phone
Tape measure/laser
Binoculars
File, plans and other supporting information
Personal protective equipment (PPE) such as a fluorescent jacket, steel-toed boots, non-slip soled shoes, ear defenders, gloves, goggles and hard hat
Pen and paper / Dictaphone

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25
Q

What should you consider when conducting an external inspection?

A

Method of construction
Repair and condition of the exterior
Car parking / access / loading arrangements
Defects / structural movement
Check site boundaries with OS map and / or Title Plan

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26
Q

What should you consider when conducting an internal inspection?

A

Layout and specification - flexibility and obsolescence
Repair and maintenance
Defects
Services - age and condition
Statutory compliance e.g. asbestos, building regulations, health and safety, Equality Act, fire safety and planning
Fixtures and fittings and improvements
Compliance with lease obligations

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27
Q

What are the different ways that you could date a building?

A

Asking the client
Researching the date of planning consent or building regulations approval
Land Registry
Local historical records
Architectural style
Architects certificate of practical completion

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28
Q

What is an inherent defect?

A

A defect in the design or material of a building which has always been present.

29
Q

What is a latent defect?

A

A defect that is not apparent upon reasonable inspection and may only become apparent after some time such as a leak in a service void.

30
Q

What is a patent defect?

A

A defect that is apparent upon reasonable inspection.

31
Q

What would you say are common causes of defects?

A

Moisture e.g. wet rot
Movement e.g. subsidence
Physical e.g. vehicle impact
Chemical e.g. efflorescence

32
Q

What are deleterious materials?

A

The term ‘deleterious materials’ is a broad one, encompassing not only materials that are dangerous to health or which are the causes of failures in buildings.

Examples include; Asbestos, Hydrofluorocarbons, Lead paint, mundic block.

33
Q

What is Japanese knotweed?

A

Japanese knot weed (Filliopia japponica) is an invasive species with no natural predator in the UK. The plant is known to grow at a rapid pace, difficult to remove and supposedly cause damage to walls.

34
Q

How do you identify Japanese knotweed?

A

The plant looks different at various times of year. In the summer;
Heart/Shovel shaped leaves
clusters of creamy white flower
Stem grows in a zig zag fashion
In the winter;
Leaves brown and drop off
Hollow bamboo like stems remain

35
Q

How do you ensure that you are safe when undertaking an inspection?

A

Adhere to RICS surveying safely 2019

36
Q

What is surveying safely?

A

RICS guidance notes that his gives guidance to firms and individuals in regard to health and safety responsibilities.

It provides advice on:

– Visiting premises and sites
– Assessing hazards and risks
– Lone working procedures
– CDM regulations
– Health and safety procedures at work

37
Q

How would you inspect a leak?

A

Visual Inspection
Electronic leak detection
Thermography
Moisture meter

38
Q

What is an EWS1?

A

An EWS1 Survey allows for the inspection of the external wall systems of a building to make sure that it does not pose a fire risk to the people that may live or work inside it. The form is valid for up to 5 years.

39
Q

What are the potential outcomes of an EWS1?

A

Option A - Where combustible materials are unlikely to be present

Option B - Where combustible materials are present

40
Q

What is an option A on an EWS1?

A

Where combustible materials are unlikely to be present

A1 - There are no combustible materials
A2 - A risk assessment identifies some remedial works
A3 - Neither of the above. The client organisation should be notified that a risk assessment is required.

41
Q

What is an option B on an EWS1?

A

Where combustible materials are present. Appointment of a fire engineer.

B1 - Fire risk is low and no remedial works
B2 - Fire risk is unacceptable and the client organisation is notified.

42
Q

What is the impact of an EWS1 survey?

A

Potential remedial works
Cost for the survey/report
Unmorgageable property

43
Q

What is a pre-acquisition survey?

A

A pre-acquisition survey enables a potential purchaser to make informed decisions about the proposed premises and its investment potential.

The survey focuses heavily on defects that affect a financial impact on the purchaser.

The result of the survey can be used in leave or purchase negotiations.

44
Q

What is a vendor survey?

A

Vendor surveys are often undertaken by commercial property owners prior to selling a building. They are objective surveys of properties intended to satisfy the due-diligence requirement of potential purchasers, avoiding the need for them to conduct their own surveys.

45
Q

What are the benefits of a vendor or pre-acquisition survey?

A

Inform terms of a lease,
Negotiations for lease or purchase sum,
Ensure that the asset is in good working order,
Plan for future liabilities.

46
Q

What is a dilapidations survey?

A

A survey associated with the making of a dilapidations claim - the overall process associated with
an allegation of a breach of lease/tenancy in relation to the condition and/or use of the property, typically as identified in a Schedule of Dilapidations, Quantified Demand and/or Diminution Valuation.

47
Q

What is a diminution valuation?

A

A valuation prepared in order to calculate the diminution in value of a landlord’s property incurred as a result of alleged breaches. The document is usually prepared by a specialist valuation surveyor.

48
Q

What is Dilapidations Protocol ?

A

Pre-action protocol for claims for damages in relation to the physical state of commercial property at the termination of a tenancy (applicable to terminal dilapidations disputes).

49
Q

What is quantified demand?

A

A document prepared for the purpose of and complying with part 4 of the Protocol,
typically incorporating a Terminal Schedule of Dilapidations. The document is usually prepared by a building surveyor

50
Q

What is a schedule of dilapidations?

A

Schedule of Dilapidations: a document that identifies:
* relevant lease/tenancy obligations
* alleged breaches of those obligations
* in certain circumstances remedial works that have
been completed or are proposed in order to rectify
each alleged breach and
* potentially the estimated or actual cost incurred in
rectifying those breaches.

The document is usually prepared by a building surveyor.

Landlords’ Schedules of Dilapidations are commonly
referred to in the following manner:
* Interim Schedule of Dilapidations: a Schedule of
Dilapidations prepared in contemplation of remedy of
any alleged breaches during the contractual term of
the lease, and not relating to yield-up obligations.
* Terminal Schedule of Dilapidations: a Schedule of
Dilapidations prepared at or shortly after the end of
the lease term. This phrase is also commonly used
in relation to a Schedule of Dilapidations prepared
in anticipation of the end of the lease term, which
includes reference to yield-up obligations.

51
Q

What is a Scott Schedule?

A

A Schedule of Dilapidations with additional columns to enable the parties to set out their respective views. The document is usually prepared by a building surveyor.

52
Q

What does a Schedule of dilapidations contain?

A

Schedules of Dilapidations would normally contain:
* details of documents relied upon
* an itemised numbered reference
* the relevant clause of the lease or other document
* the alleged breach
* the remedy required (when relevant) and
* the cost of the remedy (when relevant).

53
Q

What are common defects associated with concrete construction?

A
  • Corrosion of reinforcement and;
  • Cracking
  • Inherent defects - RAAC (strength depends on bearing and transverse reinforcement at end of panels, cut or damaged panels, signs of reinforcement corrosion)
54
Q

What are common causes of corrosion of reinforcement in reinforced concrete?

A
  • Carbonation
  • Leaching
  • Chloride-induced corrosion (cast-in or ingressing)
55
Q

What is concrete carbonation?

A

A chemical reaction where atmospheric carbon dioxide penetrates the concrete through its capillary pores. The carbon dioxide reacts with and removes calcium hydroxide. A carbonation front is established which progresses from the outer surface of the concrete inward, resulting in a loss of protection to the steel where reinforcement is in contact with carbonated concrete. Due to reduction of alkalinity of the concrete surround the reinforcement (PH will drop and loss of passive film of protection. on the reinforcement.

56
Q

How do you test for concrete carbonation?

A

The phenolphthalein indicator solution is applied to a fresh fracture surface of the concrete. If the concrete turns pink / purple , the pH is above 8.6. Where the solution remains colourless, the pH of the concrete is below 8.6 (acidic), suggesting carbonation.

57
Q

What are signs of Concrete Carbonation

A

Rust staining or exposed rebar often with poor cover.

Buildings built in the 50s and 60’s had less than 10mm of cover in places.

Surface cracking at rebar locations.

Spalling of the concrete surface.

58
Q

How Concrete Carbonation Prevented and Repaired?

A

The reinforced bar must be descaled and cleaned ready for an anti-corrosion coat to be applied. This coat isolates the bar and protects it from water and chemicals that could cause further corrosion.

Next the missing concrete needs to replaced; if a higher cement to water ratio is used then carbonation will be a slower process.

Once the repair mortar is set then an anti-carbonation coating can be applied to prevent carbonation of the concrete.

59
Q

What is leaching?

A

Where water-soluble nutrients are removed from a solid material. When water passes over the surface of concrete it will slowly reduce the calcium hydroxide levels as the solid material comes into solution to replace that lost by leaching effects of the water. Reserves of solid calcium hydroxide serves as a buffer that prevents the PH from dropping. The more acidic the water the faster and deeper leaching will be.

60
Q

What is ASR?

A

Alkali–silica reaction (ASR) is the most common form of alkali–aggregate reaction (AAR). It occurs when the alkaline pore fluid and siliceous minerals in some aggregates react to form a calcium alkali silicate gel. This gel absorbs water, producing a volume expansion which can disrupt the concrete.

61
Q

How do you identify ASR?

A

Visible as “map Cracking” in unrestrained concrete. Where the expansive forces due to ASR are restrained (eg by reinforcement or loads), the pattern of cracking is modified (Figure 2); cracks tend to run parallel to the main reinforcing bars or prestressing tendons. If the alkali–silica reaction is particularly active, the cracks may be bordered by gel. This is easily confused with, and may be mixed with, the lime which frequently leaches from cracked concrete: both turn to a whitish carbonate on exposure to the atmosphere. In general, the more colourless and jelly-like the exudation, the more certain it is that these are the signs of ASR.

The only reliable evidence for diagnosing ASR as the cause of damage is provided by microscopic examination of the interior of concrete to identify positively the presence of gel, of aggregate particles which have reacted and of internal cracking characteristic of that induced by ASR.

62
Q

What aggregates are susceptible to ASR?

A

Siliceous aggregates are the most common type of aggregates susceptible to alkali attack worldwide and are the only type conclusively identifiable in concretes damaged by ASR in the UK.

The reactive minerals found in the UK are associated with microcrystalline and crypto- crystalline quartz and chalcedony in cherts, flints and silicified limestones, and microcrystalline quartz found in quartzite and a number of other more reactive rock types. These minerals have been found in both land and sea-dredged sands and gravels. Reactive silica (microcrystalline quartz) in some greywacke aggregates can give rise to cracking at lower alkali levels than occurs with other aggregates.

63
Q

How can ASR be repaired?

A
  • Limit exposure to moisture - waterproof concrete through cladding is one possibility - but must not assist retention of water in the concrete. Where there is evidence that the expansive reaction is continuing, generally the only feasible methods are those that minimise exposure of the lament to external moisture, although gel will be present, it cannot absorb water and therefore cannot exert expansive pressure.
  • Evidence that treatment of damaged concrete with lithium salts can prevent further expansion, but no experience of this in the UK.
  • Damaged columns may be able to be reinforced around their external circumference to improve load bearing capacity and prolong life.
64
Q

How can the risk of ASR be reduced?

A

Three conditions are necessary for damaging ASR to occur:
● a sufficiently alkaline solution in the pore structure of the concrete;
● an aggregate or aggregate combination susceptible to attack by this alkaline solution;
● a supply of water sufficient to maintain the reaction and enable the gel to exert an expansive force.

65
Q

What is chloride-induced corrosion?

A

When the presence of free chloride ions within capillary pore water of hardened cement paster interferes with the passive protective film. Three ways by which chloride can be the cause of corrosion in reinforced concrete:
1. cast-in chloride ie large quantities of chloride added at the mixing stage ( calcium chloride used as accelerating admixture until 1977)
2. Ingressed ie by penetration through the outer surface of the concrete, gradually building up the chloride content at bar depth with continuing exposure
3. by an upset in the ratio of hydroxl to free chloride ions at the bar (such as in carbonation) in concrete containing low concentrations of chloride that might other wise have not caused corrosion.

66
Q

What does chloride-induced corrosion cause?

A

Likely to lead to localised breakdown of the passive film, rather than widespread deterioration. Rapid corrosion of metal can occur and cause a pit in the bar surface and significant loss in cross sectional area - pitting corrosion.

67
Q

How can chloride be remedied?

A

Chloride induced corrosion can be discrete and hard to repair. Local repairs can just shift the deterioration to an adjacent location. No safe deterioration stage like carbonation.

68
Q

How can chloride ion content be tested for?

A

Can be determined rapidly from analysis of dust collected by drilling holes into concrete. 20mm dia holes to 50mm deep. BRE information paper IP21/86 on this subject. Often completed in conjuncture with phenolphthalein test.

Cast-in chlorides are indicated by constant chloride content through the depth of the concrete.

69
Q
A