Preparing the Layer

Free O5 questions: Preparing the Layer

These questions are in the practice set above. Answer them there to see the correct option and the explanation for each.

• Scenario: a carriageway opening has been built up to the top of a bound binder course, and the surface course goes on next. During the afternoon, site traffic has tracked mud and dust across the binder course. The gang intends to spray the bond coat straight over it and then lay the surface course. Under SROH, what should happen before the bond coat goes on?
• Scenario: a gang laid and compacted the binder course in a carriageway opening on an earlier visit, and today it has come back to lay the surface course. The binder course is sound, clean and dry, but the ganger still has a bond coat sprayed over it before the surface course goes on. Under SROH, is a bond coat needed on a surface in that condition, and what does the Code ask of it before overlaying?
• Scenario: a gang reinstating a narrow trench in a carriageway has no bond coat emulsion on the van, but it does carry a bitumen emulsion edge sealant. The ganger proposes to use the edge sealant as the bond coat on the binder course before the surface course goes on. Under SROH, may it, and if so, in what role?
• Scenario: a small opening in a carriageway has been trimmed with straight, vertical saw cuts. At one corner the existing surfacing is sound, and there the two cuts have been joined by a short straight cut across the corner instead of meeting in a point. The ganger proposes to leave that corner as it is rather than saw further into the sound surfacing to cut it out square. Under SROH, is that acceptable, and what governs the treatment of that corner?
• Scenario: a small opening in a carriageway has been dug in an L shape to follow the apparatus. Its edges are saw cut straight, smooth and vertical, and the shortest projection in its outline measures 400 mm. The ganger proposes to reinstate it in that shape rather than saw out the rest of the rectangle enclosing the L. Under SROH, is that acceptable, and by what test?
• Scenario: a carriageway opening runs up to a road gully, and a stop-cock valve cover is set hard against the gully frame. Between the two features and the new edge there is a small, awkwardly shaped space. The gang intends to fill it with the same binder and surface course material it is using across the rest of the opening. Under SROH, what governs the material used in that space?
• Scenario: lifting an access cover frame in a carriageway so that it can be re-set, the gang finds it was sitting on loose engineering bricks and plastic packing pieces. The bricks are sound, and the ganger proposes to set the frame back down on them. Under SROH, what should happen to the bricks and the packing?
• Scenario: the gang is reinstating around an access cover frame in a carriageway. In the area between the frame and the point where a full depth reinstatement can be achieved, the distance between the frame and the surface is 70 mm, too little to take the binder course and the surface course at their required thicknesses. Under SROH, what does the Code allow there?

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