Some important properties of fresh concrete are given below these properties only from limited time after settled concrete you can’t realize these properties.
Workability of fresh concrete:
Workability shows a particular time in which you can handle fresh concrete, transport and use to module in any shape. Most important role in workability of water present in concrete need proper ratio. If water cement ratio is much more than required ratio then it result to non uniform composition of fresh concrete on other it is less than required ratio then you face many difficulties to handle or place it in position.
Normally, lit bit Higher water-cement ratio taken for good workability, water work like lubricant in concrete which make to helpful for handling and placing is a workable concrete.
If large amount of water added in concrete then it results to poor durability – quality and low strength. The workability of fresh concrete also affected by aggregate quality, shape, texture, grading and size also. There are type of test to check workability of fresh concrete are flow test, slump test and compaction test.
Compact-ability of fresh concrete:
In easy word compaction is process to reduce or remove void from concrete when it is in workability period. If concrete is not compacted properly then concrete loses strength considerably. Compaction help to concrete reach maximum density of concrete, presence of 5% void in concrete reduce up to 30% strength of concrete.
Some method is used to compaction of concrete are given below:
- Hand compaction
- Pressure and jolting compaction
- Vibration compaction
- Spinning compaction
Mobility of fresh concrete:
Mobility of concrete us understand by the flow of concrete into formwork around to steel and forming bonds, ability to molded.
Stability of fresh concrete:
Stability of concrete it depends how much fresh concrete remain stable without mass segregation at both time during handling and during vibration is known as stability.
Segregation of fresh concrete:
It is Separation of concrete from constituent materials each other like coarse aggregate, fine aggregate. If coarse aggregate showing tendency separating out from fresh concrete, simply it said to segregation of concrete. This type concrete didn’t gain it strength due to lack of homogeneity and it remains low strength.
Most three type of segregation are:
- In which coarse aggregate are separating out from the concrete.
- In which paste of cement is separating out from the concrete.
- In which water is separating out from the rest of materials.
Segregation properties are come from badly proportioned mix or insufficiently mixing concrete materials with excess of water content show higher tendency for segregation. To remove segregation properties of concrete need to mixing concrete by proper handling, transporting, placing and also compaction and finishing. Slump test give fair idea of the quality of concrete with respect to use for segregation properties of fresh concrete.
Consistency of fresh concrete:
Degree of plasticity or texture of concrete is known as consistency of cement concrete. It is depending on mobility or ability of fresh mixed concrete on it mortar flow properties. Wet mix design concrete can better flow than compared to dry mix design concrete.
Bleeding of fresh concrete:
It is particular type of segregation in which water separated from fresh concrete paste. Due to highly wet mix or badly proportioned mixed concrete that bleeding properties show in concrete. In bleeding come out on top surface from concrete and other materials are rest in below.
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