Failure Mode and Effect Analysis
Well, if the worst has happened and you have only found RemedyAP's services now, we will pool our experience to help you find a remedy. With decades of experience working across the corrosion and concrete protection industry, we have the knowledge to analyse your project and identify exactly where things went wrong.
Failure analysis generally means your organisation needs to identify the root cause of a failure in order to assign liability to whoever was responsible for that portion of the works. Using failure mode and effect analysis, our team can pin-point exactly what went wrong where, and who was at fault.
Get a resolution to your concrete repair or a failure of protective coatings - Contact us now!
Engineering failure analysis
Included in our free initial consultation, RemedyAP will assess your grievance and advise if there is a simple solution or otherwise provide you a proposal for further evaluation, including;
Site inspection & preliminary investigation.
Review the original project documentation & contract data.
Evaluate any available data from the project quality documentation.
Collect samples & perform laboratory testing.
Identify root cause and report on contributing factors.
Assist in any dispute resolution proceedings that ensue.
Provide expert witness testimony during any subsequent court proceedings.
Alternatively, our team at RemedyAP will advise if we can find a "remedy" that can meet your objectives and discuss possible dispute resolution options with the parties involved.
Field Survey for Paints and Concrete Repair
A field-based site survey of the affected area can reveal the conditions that promoted the failure and are useful in identifying the underlying factors that may have initiated the failure.
Coating and Concrete Surveys
Experience in failure analysis for coatings is essential to enable common sense, a critical and unbiased mode of thinking, experience, knowledge, and experimental observation.
RemedyAP key staff have the experience to observe these situations where others may not notice. This skill saves you time and money in focusing attention towards areas of key interest.
Observations and site testing can include;
- Colour testing
- Gloss testing
- Surface texture testing
- Degree of flaking
- Degree of cracking
- Degree of blistering
- Measurement of coating adhesion
- Measurement of coating thickness (DFT)
- Degree of cure
- Impact testing
- Testing for porosity
- Testing for hazardous pigments including lead (pb), Chromate and Asbestos.
- 2.Concrete Repair
- Concrete cracking
- Concrete carbonation testing
- Concrete cover thickness testing
- Concrete alkali aggregate reaction (AAR) identification
- Concrete ettringite formation
- Concrete repair mortar compressive strength
- Concrete surface tensile strength
- 3.Steel and metals
- Pit depth measurement of corrosion
- Salt contamination including chloride, sulphate and nitrates.
- Measurement of wall thickness using ultrasonic and other methods
- Surface corrosion assessment
- Positive metal identification (PMI) using x-ray fluorescence (XRF)
Digital microscopy is often used at site and at our office to help understand the coating breakdown that was occurring and the extent to which, either substrate effects or the reverse side of the applied coating contributes to the failure.
A digital microscope uses a multitude of lenses in conjunction with visible light to enhance the magnification of images especially on samples that are small. This method of microscopy allows the user to identify extremely small defects in coating continuity as well as surface defects.
The gloss loss of the Coating System can be measured and using suitable reference samples a degree of natural weathering conditions can be assessed. Any excessive loss of gloss is considered for further evaluation.
The colour can be measured using a Spectrophotometer in terms of Delta E (ΔE) values where using suitable reference samples a degree of natural weathering conditions can be assessed. Any excessive loss of colour is considered for further evaluation.
Laboratory Testing for Paints
Samples we collect during the field survey are collected under a chain of custody to ensure they can be used as admissible evidence in any subsequent legal proceedings. A range of tests are available depending on key areas of interest. These include;
Fourier transform infrared spectroscopy (FTIR) is a technique used to obtain an infrared spectrum of absorption or emission of a solid, liquid or gas. An FTIR spectrometer simultaneously collects high spectral resolution data over a wide spectral range. FTIR is used for the analysis and identification of pigments in paints/coatings by identifying unique patterns in the spectrum.
SEM and EDS Methodology
A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the sample's surface topography and composition. SEM is especially useful to scientifically verify the composition of samples used versus a known sample (control) to confirm the correct and specified materials were utilised. An energy-dispersive (EDS) detector is used to separate the characteristic x-rays of different elements into an energy spectrum, and EDS system software is used to analyse the energy spectrum in order to determine the abundance of specific elements. EDS can be used to find the chemical composition of materials down to a spot size of a few microns, and to create element maps over a much broader raster area.
An element map (a pixel by pixel image based on chemical elements) is an image showing the spatial distribution of elements as a 2D section of a known sample. Element maps are extremely useful for displaying element distributions in textural context. Using EDS, an element map can be produced. The image is produced by progressively rastering the electron beam point by point over an area of interest. Greater distinction can be made by longer analysis, but at the cost of time.
An element transect (a pixel by pixel image based on chemical elements) is an image showing the distribution of elements with depth along a known sample. Element profiles with depth are useful for displaying trends with depth.
Differential Scanning Calorimetry (DSC)
This technique accurately and reproducibly measures the difference in heat required to increase the temperature of a sample relative to a reference. Therefore, when a sample undergoes a physical and/or chemical transition this will be recorded as a heat flow change.
This technique is well suited to determining the cure characteristics of the epoxy resin via measurement of the glass transition temperature (Tg) and any residual cure exotherm.
Laboratory Testing for Concrete Core Samples
Throughout the world concrete core testing is an acceptable method for the determination of strength and quality of concrete in the structure. RemedyAP can extract core samples from your structure using a concrete core drilling machine and a water supply to lubricate the cutter. Core diameter ranges up to 125mm. The following tests may be made on cores;
Direct visual examination of concrete core
- Coarse aggregate: RemedyAP can determine nominal maximum size of aggregate, grading of the aggregate to determine if the mix is continuous or discontinuous, aggregate particle shape, aggregate mineralogy and group classification, relative proportions of aggregates, aggregate distribution in concrete.
- Fine aggregate: RemedyAP can determine nominal maximum size, grading of the aggregate and determine if its fine or coarse, type of aggregate, aggregate particle shape, aggregate relative proportion, distribution and mineralogy
- Cement: Colour of matrix of concrete.
- Concrete: RemedyAP can assess compaction, segregation, porosity, honeycombing, general composition, apparent coarse aggregate to mortar proportions, depth of carbonation, evidence of bleeding, evidence of plastic settlement, loss of bond, presence of entrained air, applied finishes, depth and other visible features, abrasion resistance, crack depth, width, other features, concrete depth, thickness, inclusions, particularly impurities, cold joints.
- Reinforcement: Type (round, square, twisted, deformed), size, number, depth/cover
- Core drilling faults: RemedyAP will report on physical characteristics of the core to include presence of bowing and/or ridges
Indirect visual examination of concrete core
- Before trimming and capping (by microscopic or petrographic techniques) RemedyAP can: Determine mineralogy, quantify air, sand content, bubble, void size & spacing, microcracking, surface texture of coarse aggregates, fine aggregate particle shape, maximum size of aggregate, aggregate grading, and degradation.
Routine physical tests of concrete cores
- The core sample requires capping before compression testing. Prior to capping RemedyAP can assess: density and water absorption.
- Ultrasonic-pulse velocity can assess the homogeneity of concrete and properties that change with time.
Concrete core compressive strength
The compression strength of concrete is a measure of the concrete's ability to resist loads which tend to compress it. It is measured by crushing cylindrical concrete core specimens in a compression testing machine.
Special Physical tests of companion concrete cores:
- Indirect tensile strength, Abrasion resistance (surface only), Frost resistance, Movement characteristics.
- Routine chemical tests of cores after crushing for strength: aggregate/cement ratio, type of cement, aggregate grading (recovered), sulphates, chlorides, contaminants, admixtures.
- Accurate pH profile of concrete is determined at numerous depths by testing at different depths, taking samples from the cores at every 10mm.
Determination of water to cement ratio.
The quantity of water used in mixing concrete is very important. If the percentage of water used is less then there shall not be sufficient quantity of water to hydrate cement. It shall result in porous and weak concrete. However, the usual tendency is to use too much water which gives a more workable mix but it does not give sound concrete. Too much of water results in segregation of aggregates and gives porous concrete of low strength and low density.
Special tests on core after crushing for compressive strength:
- Sulphate attack, cement and other minerals and mineral phases, and molecular groupings such as NaCl, CaCl2, SO3, C3A. Contaminants, chloride attack, and high alumina conversion,
Alkali Aggregate Reactivity (AAR)
- Both subsets of AAR being alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR) can be identified using a petrographic microscope. Alternatively, polished sections of concrete can be examined by scanning electron microscopy (SEM); this has the advantage that the gel can be analysed using X-ray microanalysis to confirm the identification beyond any doubt.
- Microscopically, ettringite takes the form of massive aggregates or bands at the aggregate–cement paste interface, causing debonding, or filling cracks, accompanied by air voids almost filled by ettringite.
Alternatively, the team at RemedyAP will advise if they can find a "remedy" that can meet your objectives and discuss possible dispute resolution options with the parties involved.
Contact our experienced team today to find out exactly how we can help you. We can discuss your particular issue and decide on a path that will lead to the best results for your organisation. Click here to get in contact with one of our team.