Design of special Pavements

(as per IRCSP 20-2002)

Presented by: RUOKUOMENUO RIO

M.Tech HT , 1st Semester Rural Roads

Lecture-in-charge: Mrs.Ranjitha J

Special pavements

DOUBLE HERRINGBONE (pattern adopted)

Design criteria1. Materials for special pavement

i.e Concrete Block Pavement (CBP)/Interlocking Concrete Block Pavement(ICBP)

2. Concrete mix3. Specifications4. Stone-sett pavement or bridge on edge

pavement

1.Materials for special pavement

Concrete Block Pavement (CBP)

Concrete blocks are used which are non-interlocking when paved.

Interlocking Concrete block Pavement (ICBP)

Blocks with curved vertical faces are used.

CBP/ICBP Produced from Block Making Machines (BMM) Blocks are allowed to self cure under ambient

temp. i.e 24 hours during mild season and 12 to 18 hours during summer.

Transferred to curing tanks or gunny bags- cured for 28 days to achieve full strength

When BMM’s are unavailable, manual or semi-automatic hydraulic presses are utilised.

Manual or power driven mixers are used for preparation of concrete mix.

Curing is done either in curing tanks- capacity for holding 2 weeks’ production of blocks or else by wet gunny bags or hessian cloth.

Fig 1: Block Making Machine

Produces ICBP, building blocks, kerb stones etc.High standard and meets international quality requirements.ISO certified

Fig 2: Curing tanks

Paving block curing

Gunny bags/hessian cloth

Curing being done in columns using gunny bags (inset)

General features and requirements:

Consists of surface layer of brick-sized concrete blocks paved on thin, compacted bedding sand layer of specified grading.

Spread over profiled base course bounded by edge restraints .Joints are sealed with joint filling sand.

A good drainage layer is provided over compacted sub-grade for satisfactory performance of CPP/ICBP.

Edge restraints

2.Concrete mix

Ordinary Portland cement/ Portland Pozzolana Cement/Portland Slag Cement are used as binders.

Good quality natural coarse and fine aggregates as per IS:383-1970 should be used in concrete.

Industrial waste material such as fly ash ,slag etc. can be used as additives.

Potable water should be used for making concrete mix.

Blocks so produced should have equivalent 28-days strength as per design requirements.

Grading of concrete mix

Serial no Blocks meant for Grade

1. Paving rocks carrying traffic

M-30 or higher grade

2. Non-traffic area like footpaths

M-25 or higher grade (60mm thick block)

3. Precast edge restraints

M-25 or higher grade (1:1:2)

3.Dimension and ThicknessSerial no Type Specification (as per

IS:SP20-2002)

1 Precast edge restraint 150X150X300 mm

2. Top surface area of blocks

200-500cm²

3. Breadth-to-length ratio of rectangular blocks

1:2

4. Length of rectangular blocks

200 to 220mm

5. Width of rectangular blocks

100 to 110 mm

6. Colour of block Natural cement or special colour by using organic or inorganic pigments.

Serial no Type Specification

7. Cement treated marginal agg. as base course

67 per cent of the granular base course.

8. Lime fly ash bound macadam and lime fly ash concrete as base layer

67 per cent of the base course.

9. Bedding sand Thickness of 30mm

10. Base course Minimum thickness 100mm

Natural sandstone used for paving.

Design chart for granular base i.e Thickness of granular base layer

Eg: For 54 CVPD, and CBR=4% thickness=250mm

Recommended grading for bedding and joint filling sand.

Serial no

IS Sieve size (mm) Zone- II (IS:383-1970)(for bedding sand)Per cent passing

Zone- IV (IS:383-1970)(for joint Filling Sand)Per cent passing

1. 10.00 100 100

2. 4.75 90-100 95-100

3. 2.36 75-100 95-100

4. 1.18 55-90 90-100

5. 0.60 35-59 80-100

6. 0.30 8-30 15-50

7. 0.15 0-10 0-15

8. 0.075 0-3 0-5

4. Stone-sett pavement/brick on edge pavement It is used only

for areas having very poor drainage and pedestrian pathway.

Cobblestone available from river beds can also be used for paving.

Brick on edge pavement

Cobble stones

Type of stones normally used for stone-sett pavements are:-Granite Basalt

Sandstone Limestone

Bricks are laid on edge over bedding sand.

Specification of stone-sett/ brick on edge pavement.

Stone cut to regular sizes should normally have dimension of 100 to 150mm diameter and 90 to 100mm thickness.

For brick pavement, burnt clay or bricks having minimum 28 days compressive strength of 7MPa.

Availability of Concrete Block Pavements in various shapes and sizes.

Reference:IRC SP 20:2002Google images