Testconsult provides a full range of NDT and inspection techniques to assess the condition of concrete and masonry structures and in particular bridge structures. Concrete is not the all-enduring material it is often thought to be and many poorly designed or constructed structures require considerable maintenance to prolong service life. Structural investigations can include tests to identify poor materials, environmental contamination from road salts, sulphates and carbon dioxide to offer valuable information to the engineer to determine refurbishment cost and future life. Projects frequently carried out include:
- Post-tensioned bridge inspections – to check the condition of tendons
- BA 35/90 bridge inspections, Car park assessments, culvert surveys – to check the condition of concrete & reinforcement
- Floor humidity monitoring
- HAC determination – to check for the presence of and the degree of conversion
- Diamond coring, sampling and concrete strength assessment
- Impulse Radar – to check the positioning of ducts and tendons
- Bomb and fire damage assessment – to check for degradation of concrete & reinforcement
Post – Tensioned Bridge Inspections
The post-tensioning of steel tendons in concrete beams has been widely used in both road and rail bridges. Normally the tendons are carried in ducts which are injected with grout to protect the tendons from corrosion. Where the injection process has been unsuccessful the tendons are left unprotected and prone to corrosion. This process may be accelerated if the concrete is contaminated, for example with chlorides from de-icing salt. A typical inspection of a post-tensioned bridge may involve several of the following test methods :
- Impulse Radar – using a high frequency antenna to locate rebars and tendon ducts
- Intrusive Surveys and duct inspection by drilling and using a flexible video-imagescope.
- Pressure testing to establish the size of any voids
- Chemical testing to check for chemical contaminations
- In-situ Stress Determination to check existing stresses in both concrete and steel
This is in addition to the more traditional concrete testing methods, including Half Cell Potential, Cover surveys, Resistivity, Rebound hammer, Diamond coring etc.
Testconsult has over 20 years experience in this field of work. With this capability we can give civil, structural and consulting engineers advice and cost effective solutions. Our structural investigation section can carry out appropriate surveying, sampling and testing to identify the causes of premature degradation and advise on the most appropriate remedial action required.
Range of In Situ Tests available:
Depth of cover
Half-cell potential mapping
Depth of carbonation
Resistivity
Delamination surveys
Rebound Hammer surveys
Pull-off and pull-out tests
Borescope inspection
Humidity and moisture levels
Ultrasonic surveys
Range of Sampling techniques employed:
Incremental dust sampling
Core sampling
Steel sampling
Paint and coating sampling
Range of Laboratory tests offered:
Chloride ion content
Sulphate content
Cement content
Compressive strength tests
Petrographic examinations
HAC - presence and condition
ASR - Presence
Thaumasite reaction identification
Steel - identification of type and yield strength
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