Crack (Part 7)


17.6 Cracks of Steel Reinforced-Pavement

A. Crowfoot Crack: this crack is often either parallel with pavement or making certain angle with Expansion Joint. Occurrence of crowfoot crack is attributable to expansion of material used to fill up the Expansion Joint, which develops toward the edge of pavement. Or water/other chemical substances permeate through Expansion Joint or Contraction Joint.

B. Corner Break: the characteristic of this corner crack is similar to triangle, which its dimension in each side is greater than 45 cm. For the reason that cracks initiate is due to the pavement has to withstand to excessive loads fatiguingly and impulsively.

C. Diagonal Crack: this crack is formed diagonally to the pavement due to disproportion of bearing capacity of subgrade, which brings different settlement throughout the terrain or affected by change of soil volume.

D. Spalls: this crack can be found on every type of joints or interconnection of two joints. Because of incompatibility in material selection and designing of contraction joint or water/other chemical substances are subject to permeability above the joint.

E. Transverse Crack: owing to length of pavement is large and no contraction joint provided for such length, this results crack to occur in transverse direction to the pavement.

F. Transverse Crack: this type of crack occurs in transverse direction to the pavement, which approximately located at 120 – 150 cm. away from contraction joint. As a result of reduction in soil bearing capacity, it is attributable to weathering of existing soil by mean of water. This incident is called “Pumping Phenomenon”, which water will push out soil through leakage of that water permeate in. Thus, existing soil can no longer be bearable and eventually induces cracks.

G. Longitudinal Crack: this type of crack occurs along the length of pavement due to the pavement has large width with no joint cutting through the middle.

H. Plastic Shrinkage Crack: feature of this particular crack is known as crazing, which resulted from rapid loss of water of fresh concrete due to prior curing is insufficient, fast evaporation above the surface or existing soil/aggregate is completely dried out, which water will be promptly used up.

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