During all the above-mentioned operations of mixing, spreading, compacting and levelling of sub-base and base courses material, care must be taken so that layers already compacted under the layer being executed are not affected, or that the finished sub-grade or base surface is also not affected. This aspect must be given special attention in places where equipment makes turns in going back and forth and any such damage resulting in mixing the various layers constituting the different sub-grades and base courses shall be carefully made good by the Contractor at his expense and to the satisfaction of the Engineer.
If more than one sub-base or base course is required for reaching the required thickness described in the Specifications, each such course will be constructed as hereinbefore described.
Where the finished compacted thickness exceeds 150mm placing shall be executed in composite layers each layer not exceeding 150mm in compacted thickness as directed by the Engineer.
303.03.5 Protection of Surface
The Contractor shall protect the sub-base or base course so that it shall be maintained sound during work progress, after its completion and prior to receiving the bituminous layers or prior to laying the surface overlay thereon. Any damage caused to the layer if exposed to traffic or natural conditions resulting in damage of its surface should be made good at the expense of the Contractor and to the satisfaction of the Engineer.
The sub-base and base courses shall not be rolled when the underlying material is soft or yielding or when the rolling causes a wave-like motion in this course.
When the rolling develops irregularities, the irregular surface shall be loosened, then refilled with the same kind of material as used in constructing the course and again rolled according to specifications. Along places inaccessible to rollers, the sub-base and base courses’ material shall be tamped thoroughly with mechanical tampers.
Work on the sub-base and base course shall not be permitted during rainy weather. Hauling equipment may be routed over completed portion of the sub-base and base courses provided no damage results and provided that such equipment is routed over the full width of the course to avoid rutting or uneven compaction.
The Engineer has the right to stop all hauling over completed or partially completed sub- base and base courses when in his opinion such hauling is causing damage.
303.03.6 Preparing the Surface Before Priming
Following the completion of the base course and sub-base courses the Contractor shall perform all maintenance work necessary to keep the course in a condition for priming. The prime coat shall be applied after preparation of the previously compacted surface, all in accordance with Clause 405 of these Specifications.
303.03.7 Testing and Acceptance of Aggregate Sub-base and Base Courses
Prior to the application of any prime coat or any other paving course, the aggregate sub- base and/or base course shall have been tested and accepted by the Engineer. The following shall be adhered to in accepting completed aggregate sub-base and base courses:
a. Strength Specification for Compacted Aggregate Sub-Base and Base Courses
The aggregate sub-base and base courses shall be compacted and tested for acceptance in accordance with the compaction requirements of Section 303.03.3 of these Specifications.
In addition, the sub-base and base courses shall be tested for the degree and uniformity of stiffness by measuring the in-situ deflections. The test method will be a measurement of dynamic deflection using the Dynaflect equipment.
The results of Dynaflect testing shall be considered a measure of conformance to specification requirements for aggregate sub-base and base courses.
Dynaflect testing shall be performed on permanent works and on Type IV – Long Term Detours.
SECTION 3 SUB-BASE AND BASE COURSES
Depth of fill, mm Wl limits – mill inches
Sand gravel
Base of 150 mm on cut or fill layers
0 150 300 450 600 750 900 1000 or more 1.40 1.34 1.28 1.26 1.24 1.22 1.20 1.20 Sand gravel Base of 300 mm on cut or fill layers
0 150 300 450 600 750 900 1000 or more 1.06 1.02 1.00 0.98 0.98 0.96 0.96 0.94 Table 303.03.7
Dynaflect testing shall be performed longitudinally across the full width of the sub-base or base course. Testing will be at maximum intervals of 25 metres and representing a maximum width of 4 metres.
A minimum of 5 tests shall be made on every strip tested.
The Contractor shall be notified by the Engineer that the tested layer is accepted or rejected within 24 hours, excluding Fridays and Kuwait holidays, following the time the Dynaflect test was made.
Where Dynaflect test results fail to meet minimum deflection requirements, the Contractor shall at his expense rework, recompact or if necessary remove and replace the work as required to produce satisfactory test results.
In the event that Dynaflect testing of a layer is not possible, the work may be accepted at the discretion of the Engineer on the basis of satisfactory density results. In such cases, however, the subsequent layer shall only be accepted on the basis of Dynaflect tests.
b. Requirements for Compaction
Wherever the degree of compaction is found to be less than the 95% specified, the area of sub-base or base course involved shall be satisfactorily corrected so that the specified density is achieved.
c. Requirements for Gradation
Wherever the gradation is found to be outside the limits specified, the area of sub-base and/or base course involved shall be scarified, removed or otherwise reworked as directed by the Engineer to provide a material within specification limits.
d. Requirements for Thickness
Wherever the thickness of compacted aggregate sub-base or base course is found to vary from the plan thickness by more than 10% the area involved shall be satisfactorily corrected to provide the required thickness constructed to the specified grade level. e. Requirements for Evenness of Surface and Grade Levels
The final surfaces of the sub-base or base course shall be tested by means of a 4 metre long straight edge, and no rises or depressions in excess of 10 mm shall appear in the surface. Likewise the finished surface shall be constructed to the specified grade levels to within 10 mm.
Where these requirements are not met, the Contractor shall determine the full extent of the area which is out of tolerance and shall make good the surface of the course by scarifying to a minimum depth of 75 mm or 4 times the maximum particle size, whichever is the greater, reshaping by adding or removing material as necessary and recompacting in accordance with the Specifications.
303.04 MEASUREMENT AND PAYMENT OF THE AGGREGATE SUB-