Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 10: Roads, Landscaping and Fences  Where surface water drainage is provided for roads it shall consist of piped drainage. Where practicable drainage work shall be completed before road works is commenced.  Trenches for piped drainage shall be excavated to the minimum dimensions necessary for the proper  construction of the Works, and after pipes have been laid, tested and, where specified, surrounded with  gravel or concrete, the trenches shall be backfilled with excavated material and compacted to a dry  density equal to that of the adjacent ground. Surplus excavated material shall be disposed of offsite.  Porous pipes shall be laid dry-jointed and shall be surrounded with gravel.  Soak-away ponds and in-situ concrete catch pits with kerb weirs shall be constructed Brickwork manholes and gullies shall be constructed complete with cast iron covers or gully gratings.  Open drainage channels for roads shall be constructed as concrete channels with a width up to 1 m and  a depth up to 0.5 m. The bottom of the trench and the lower part of the slopes (1/3 of the total depth)  shall receive stone pitching as described in the herewith Employer’s Requirements. The works to be  carried out shall include the required excavation, the trimming, compaction and pitching of surfaces  and site clearance after completion of the works. Kerbs, edgings, channels and quadrants shall be laid and bedded on a layer of mortar, either on the  concrete carriageway or on a Grade C20/25 concrete foundation. They shall be butt-jointed except  where otherwise described in the Contract, save that where laid on concrete carriageways they shall be  provided with joints coincident with the carriageway movement joints, of width and with filler identical to that used in the carriageway joints. All kerbs shall be backed with Grade C20/25 concrete.  Alignment of kerbs and channels shall not deviate from that described in the Contract by more than 10  mm, with no lipping of visible faces.  Foundations for footways shall consist of granular sub-base material spread evenly and compacted in  layers of not more than 100 mm thickness.  Compaction to the correct levels shall be carried out using a vibratory roller have a static load of at  least 1000 kg/m width of roll.  Pre-cast concrete flags shall be laid to falls on sub-base material, bonded with joints at right angles to  the kerb, and spot bedded with mortar with no lipping of top surfaces.  Flags shall be cut to fit around surface boxes and other furniture and, on circular work where the radius is 12m or less, shall be radially cut on both edges to the required lines.  Pre-cast concrete block paving shall be used.  Finished surfaces at each stage of road construction shall not vary from the levels described in the  Contract by more than the following permissible deviations:  10_Vol3_d4.3_Section 10 roads, landscaping and fences_en_GIR_rev6.docx  10.1.20 Tolerances for finished carriageway surfaces  10.1.19 Laying paving blocks  10.1.18 Laying concrete paving flags  10.1.17 Foundations for walkways  10.1.16 Laying kerbs and channels 11 of 15