hardened concrete Flashcards
is a type of evaluation that determines how a component will behave under pressure until it fails
Destructive testing
assesses an object’s behavior but does so without the need of damaging it.
Non-destructive testing
Non-Destructive Tests
Rebound Hammer
Ultrasonic Pulse Velocity
Destructive Test
Compression Test
is a non-destructive method of testing concrete which provides a quick indication of compressive strength of the subjected surface.
Rebound hammer testing
RHT procedure
Preparation: Clean the surface of the concrete to remove any loose particles, dust, or debris. If the surface is too smooth, roughen it with a grinder or papel de liha (sandpaper).
Calibrate the hammer: Press the hammer onto a hard, flat surface to make sure the needle on the dial reads zero. If it doesn’t, adjust the instrument accordingly. (80±2)
Test locations: Determine the locations where you will conduct the test. It’s recommended to test at least 3 spots on the concrete surface to ensure accuracy.
Conduct the test: Hold the hammer perpendicular to the concrete surface, with the impact plunger touching the surface. Press the trigger to release the plunger, which will hit the surface with a spring-loaded mass. The rebound energy will cause the plunger to bounce back, and the hammer will record the rebound distance.
Record data: Record the rebound values on a data sheet, making sure to label each value with its corresponding test location.
[Interpretation: Use the rebound values to estimate the compressive strength of the concrete. Consult the manufacturer’s instructions or a conversion chart to convert the rebound values into compressive strength values.]
influencing factors (hardened concrete)
Type of Aggregate
Type of Cement
Surface and moisture condition of the concrete
Curing and Age of concrete
Carbonation of concrete surface
Helps engineers in the quality control of newly constructed and existing concrete structures. Evaluate the integrity and quality of concrete materials and structures.
Ultrasonic pulse velocity
ultrasonic pulse velocity method could be used to establish:
the homogeneity of the concrete,
the presence of cracks, voids, and other imperfections,
changes in the structure of the concrete which may occur with time,
the quality of the concrete in relation to standard requirements,
the quality of one element of concrete in relation to another, and
the values of the dynamic elastic modulus of the concrete.
upv applications
Durability of Concrete
Defining internal flaws
Segregation
Honeycombing
Compaction of Concrete
Workmanship
factors affecting resulst (upv)
Quality of the Testing Surface and Tramsducer Contacts
Path length of the pulse
Dimension of the specimen tested
Presence of reinforcement in concrete
Size of the aggregates used
Moisture content of tested concrete
Concrete Age
Cement Type
upv apparatus
upv meter
upv procedure
Preparation of Specimen: Concrete Surface Preparation
- Locate the dry location on the concrete surface.
1.2. Use a grinding wheel to remove any plaster or other coating from the concrete surface.
1.3. Divide the entire structure in suitable grid markings of 300 mm
Ultrasonic Measurement: Placement of the Two Transducers on a Concrete Surface
a.) Direct transmission method (Fig. A): Both transducers are placed on opposite faces of the concrete surface
b.) Semi-direct transmission method (Fig. B): Both transducers are placed on adjacent faces of concrete surface
c.) Indirect or surface transmission method (Fig. C): Both transducers are placed same face of the concrete surface
Procedure of Ultrasonic Pulse Velocity Test for Different Transducer Arrangements
3.1. Measure the distance between the grid points where the transmitting and receiving transducers are to be placed. (L)
3.2. Apply typical acoustical couplants like petroleum jelly, grease, or liquid soap between the concrete surface and the face of each transducer.
3.3. Switch on the ultrasonic pulse velocity meter then press the transmitter and receiver transducers on the predetermined grid points of the concrete surface.
3.4. Record the traverse time (T) displayed on the ultrasonic pulse velocity meter.
is used to determine how a product or material reacts when it is compressed, squashed, crushed or flattened by measuring fundamental parameters that determine the specimen behaviour under a compressive load.
compression testing
benefits of using compression testing
To determine batch quality
To determine consistency in manufacture
To aid in the design process
To reduce material costs and achieve lean manufacturing goals
To ensure compliance with international and industry standards