Term: Concrete slump test
– Procedure:
– Slump cone
– Tamping procedure
– Removing cone
– Height measurement
– Test uses a metal mould called a slump cone with specific dimensions for fresh concrete placement and tamping to measure slump.
– Interpretation of results:
– Types of slump include collapse, shear, and true slump
– True slump is the only useful result
– Different slumps indicate workability levels for various construction needs
– Shear or collapse slumps may require retesting with a fresh sample
– Concrete slump shapes determine the type of slump achieved
– Limitations of the slump test:
– Suitable for medium to low workability concrete
– Cannot determine workability in stiff or wet mixes
– Limited to aggregates less than 38mm
– Test range is from 5 to 260mm slump
– Inappropriate for high workability mixes with collapse slumps
– Differences in standards:
– ASTM C94 and AASHTO provide specifications in the U.S.
– Standards vary in different countries like the UK and Europe
– Details of slump cone dimensions and testing procedures differ
– Standards regulate the rigidity of the cone and lifting method
– Codes like ASTM C 143 and AASHTO T 119 define the concrete slump test
– Other tests:
– Flow table test and K-Slump Test are alternative methods
– Various tests evaluate concrete consistency and flow
– Automated slump meters are used to measure and display slump
– Some meters can add water to concrete mix during transit
– Standards like ASTM International accept automated slump meters for accuracy
The concrete slump test measures the consistency of fresh concrete before it sets. It is performed to check the workability of freshly made concrete, and therefore the ease with which concrete flows. It can also be used as an indicator of an improperly mixed batch. The test is popular due to the simplicity of apparatus used and simple procedure. The slump test is used to ensure uniformity for different loads of concrete under field conditions.
A separate test, known as the flow table, or slump-flow test, is used for concrete that is too fluid (non-workable) to be measured using the standard slump test, because the concrete will not retain its shape when the cone is removed.