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The combination of permitted tolerances in the levels of different pavement courses shall not result in a reduction in thickness of the pavement, excluding the sub-base, by more than 15 mm from that specified, and the maximum allowable irregularly of the wearing surface below a 3 m straight edge shall be 3 mm. 

## 10.1.21 Tiled pavements 

Tiled pavements for walkways consisting of approved concrete slabs with a minimum thickness of 50 mm shall be laid on 20 mm of sand for final leveling. All slabs shall be of approved type and design and shall be firmly bedded on the underlying course and shall be laid against each other. Upon completion of the slabs sand shall be strewed, and be compacted with a mechanical vibrating machine of sufficient weight. The application projects shall be prepared by the Contractor and shall be subject to approval of the Engineer. 

## 10.1.22 Pre-cast units for kerbs and surface drainage 

Kerbs and drains units shall be supplied and laid along the roads and parking areas to be constructed on site. 

Curves shall be provided with specially made bends as follows: 

Curbs shall not be laid until the 28 day strength of the pre-cast unit is attained. Kerb sections shall be set on compacted sub-grade. Any section deviating in line or level by more than 1 mm in 1 m shall be lifted and re-laid. Joints shall be grouted up with mortar. The application projects shall be prepared by the Contractor and shall be approved by the Engineer. 

## 10.1.23 Concrete 

The quality of the concrete surface course, tiled pavement, kerbs and units for surface drainage shall be according to Section 6 of these Specifications. 

## 10.2 Fences and Gates 

## 10.2.1 General 

The fence on concrete parapet shall surround the whole wastewater treatment plant site. 

## 10.2.2 Fences 

The permanent fence shall consist of a galvanized steel wire mesh with 50 x 50 mm openings, and three rows of barbed wire above the steel mesh. Height of steel wire mesh shall be 2.40 m and the distance between each barbed wire shall be 0.10 m. Total height of the fence 2.70 m. The poles bearing the barbed wires bend 30 degree from vertical to the WWTP site. 

Fence poles per 3.00 m shall be galvanized iron pipe Ø 100 mm, t = 6 mm. The steel mesh shall be secured to the posts at 0.30 m intervals along the height of the posts and the chain link fence shall be supported by fixing to 3 wires strung from post to post. Furthermore, the steel mesh and posts shall be embedded in the concrete foundation. 

