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Following is a question by the Hon Mrs Sophie Leung and a written reply by the Secretary for Works, Mr Lee Shing-see, in the Legislative Council meeting today (May 31) :

Question:

Regarding the use of precast paving slabs for pavements, will the Government inform this Council:

(a) how the cost per square metre for pavements using such materials compares to that for pavements using cement?

(b) of the average frequency of repair required for these pavements and the average cost per square metre for such repairs? and

(c) whether rugged surfaces or damaged slabs are common on these pavements; if so, of the reasons for that and the improvement measures that can be taken?

Reply:

Madam President,

(a) The average construction costs of concrete footpath and ordinary paving block footpath are $58 per sq. m and $ 97 per sq. m respectively, based on the current contract price. In spite of the large difference in direct unit cost, paving block footpaths present the following benefits, particularly in the environmental aspects :

(i) Lower cost of repair. Paving blocks can be re-used in subsequent pavement reinstatements and should be adopted at locations susceptible to excavations by utility undertakers.

(ii) Minimal noise and dust nuisance. Paving blocks can be lifted and re-laid quietly. On the other hand, the reinstatement of concrete pavement is nosier and dusty as it involves the breaking up of existing concrete

(iii) Paving blocks result in less construction waste than concrete, which needs to be disposed of at public filling outlets or landfills. At present, the government is paying landfill operators about $125 for each tonne of demolished material disposed of at the landfills. This represents about $27 per sq. m of 75mm thick of concrete footpath. Compared to concrete pavement, this is an additional cost savings if paving blocks are used.

(iv) Paving blocks are easy to lay and can be walked on instantly without having to wait for the concrete to harden.

(v) Paving blocks have unique aesthetic benefits, particularly when special patterns and colours are designed.

(b) Under normal load conditions, all paving block footpaths are serviceable within their life expectancy. Even in the case of excavation for utility installations, the existing paving blocks are not supposed to be easily damaged. However, where the design load capacity is exceeded, the footpaths would be susceptible to damage and may need to be repaired. Such overloads may arise from a number of external factors such as heavy usage, illegal parking, frequent loading and unloading activities.

The cost of repair is basically similar to the construction cost. However, if the existing paving blocks can be reused (e.g. overloading by illegally parked vehicles causing uneven surfaces) the cost of repair can be reduced by about 35% (i.e. about $65 per sq m).

(c) There should be no rugged surface on paving block footpaths that are built in compliance with standards. The cases of damaged paving blocks are also uncommon. The Highways Department has been carrying out regular road inspections (including footpaths) and operating a telephone hotline around the clock. Should any defects be identified or reported, the Highways Department would arrange for them to be repaired as soon as possible. From past experience, cases involving damaged pavements or rugged surfaces have been very often associated with illegal parking overloading the footpaths. Depending on the circumstances, the Highways Department can take a number of measures to curb illegal parking such as installation of bollards or railings along the footpaths.

End/Wednesday, May 31, 2000

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