Properties of Green Concrete are following:
1. Workability: It is defined with which concrete can be compacted fully without segregating and bleeding as the ease. It can also be defined as the amount of internal work which is required to fully compact the concrete to optimum density. Workability depends upon the quantity of water, shape, grading and in the concrete the percentage of the aggregates present.
Workability is measured by following
- With concrete is lifted and removed when the frustum of the standard cone filled the slump observed after allowing the concrete to fall the compaction factor determined through the compaction testing machine.
- When tested in Vee-Bee consist meter, the time taken in seconds for the shape of the concrete to change from cone to cylinder.
Suggested values of workability for different works are as shown in given table
Suggested values of workability
2. Segregation: from the green concrete Separation of coarse particles is called segregation. Due to lack of sufficient quantity of finer particles in concrete or due to throwing of concrete from greater heights at the time of placing the concrete this may happen. The cohesiveness of the concrete is lost and honey combing results because the segregation. It results in the loss of strength of hardened concrete ultimately. Therefore utmost care is to be taken to avoid segregation.
3. Bleeding: on the surface of the freshly laid concrete, this refers to the appearance of the water along with cement particles. When there is excessive quantity of water in the mix or due to excessive compaction this happens. Bleeding is reason for the formation of pores and renders the concrete weak. By suitably controlling the quantity of water in the concrete and by using finer grading of aggregates bleeding can be avoided.
4. Harshness: By concrete to its surface finish, Harshness is the resistance offered. Harshness is happen due to use of poorly graded aggregates or due to presence of lesser quantity of fine aggregates, lesser cement mortar and. due to insufficient quantity of water It also may result. It is difficult to get a smooth surface finish and concrete becomes porous with harsh concrete.