Grameen Sampark Final April 0... - pmgsy

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12 Typical Pavement Compositions Typical compositions normally used in ICBP technology are given in Table-2 with typical cross sections as shown in Figure 4. Grameen Sampark BLOCK PAVED SURFACE BASE COURSE SUBGRADE Figure 4: Typical Pavement Structure Drainage JOINT FILLING FINE SAND INTERLOCKING CONCRETE BLOCK COARSE BEDDING SAND Table 2: Catalogue for Pavement Thickness EDGE RESTRAINT SHOULDER Traffic and Road Type Materials >10 Sub grade CBR (%) 5-10 Thickness (mm)
Block Pavement at Typical Locations Essentially, there are three important aspects in detailing. These are: (i) Curves (ii) Intrusions, and (iii) Changes in alignment Curves: It is necessary to cut the paving units to fit the edge restraints. Rectangular blocks of similar or contrasting colour as an edging have been used to minimize the visual effects of small errors in block cutting. To avoid unsightly and potentially weak joints, it is often preferred to change the laying pattern at the curves. The curve itself can be installed in Herringbone bond and yet the pavement can revert to stretcher bond on the approaches [4 & 5]. Intrusions: On some pavements, like in city streets, there could be several intrusions, like, manholes, drainage gulleys, etc. where coping with these intrusions with the pavement is desirable. Around intrusions, it is good practice to lay blocks along both sides of the intrusion simultaneously so that closure is made away from the starting workface, rather than carrying the pavement around the intrusion to return to the original laying face to avoid accumulation of closing error [7]. Compaction For compaction of sand bedding and paving blocks laid over it, the vibratory plate compactors are used over the laid paving blocks; at least two passes of the vibratory plate compactors are needed. Such vibratory compaction should be continued until the top of each paving block is in level with the adjacent blocks. It is not a good practice to leave compaction till the end of the day, as some blocks may move under construction traffic, resulting in the widening of joints and corner contact of blocks, which may cause spalling or cracking of the blocks. There should not be any delay in the compaction after paving blocks have been laid. This is necessary to achieve uniformity of compaction and retention of the pattern of laying. During compaction of the blocks laid, some amount of bedding sand may get filled up into the joints between them; the extent of sand Pradhan Mantri Gram Sadak Yojana getting filled up into the joints will depend on the degree of compaction of sand, i.e. the force applied by the compactor. Standard compactors may have a weight of about 90 kg with plate area of about 0.3 m2 and apply a centrifugal force of about 15 kN. On the other hand, heavy duty compactors may weigh 300-600 kg, with plate area of about 0.5-0.6 m2 and apply a centrifugal force of 30-65 kN. Where the bedding sand is required to be compacted for heavily trafficed pavements, heavyduty compactors should be used. After compaction by vibratory plate compactors, some 2 to 6 passes of vibratory roller (with rubber coated drums or those of static weight less than 4 tonne and nominal amplitude of not more than 0.6 mm) will further help in compaction of bedding sand and joint filling [7]. Laying and Surface Tolerances While constructing the block pavement, the surface toleranes of individual layers may be observed, as indicated in IRC:SP:63-2004. Conclusion ICBP technology is gaining importance and is becoming more popular day-by-day because it is user friendly and requires less infrastructure in terms of construction equipment / machineries, as compared to the conventional flexible and rigid pavements. ICBP technology can provide durable and sustainable road infrastructure where construction and maintenance of conventional pavements are not cost effective. ICBP is much cheaper than the rigid (concrete) pavement, designed for identical operating conditions. Compared to the bituminous pavement for low traffic volume roads and high strength subgrade, the initial construction cost of ICBP is likely to be equal to or marginally higher. For high traffic volume roads and low strength subgrade, ICBP will be cheaper than the flexible pavement. Grameen Sampark 13
Page 2 and 3: In this Issue Editorial 3 Potential
Page 4 and 5: 4 Potential Applications of Interlo
Page 6 and 7: 6 Interlocking Concrete Block Pavem
Page 8 and 9: 8 materials used for production of
Page 10 and 11: 10 Construction of Sub grade This i
Page 14 and 15: 14 Guidelines for the use of In
Page 16 and 17: 16 layers due to repeated applicati
Page 18 and 19: 18 Subgrade Failure Criterion The b
Page 20 and 21: 20 A maximum of 50mm rut depth was
Page 22 and 23: 22 Stabilization of Soil Subgrade w
Page 24 and 25: 24 Changes in Cohesion and Direct
Page 26 and 27: 26 Increase in the C.B.R. value is
Page 28 and 29: 28 Laboratory Test (Under Vertical
Page 30 and 31: 30 Apart from the above, both faces
Page 32: News in Brief General Body Meeting

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