1. PRESENTATION ON FLOATING ROADS BY MARTIN HMENSA DEPARTMENT OF FEEDER ROADS, GHANA

2. OBJECTIVE To share the successful results of constructing roads on peat with sand and gravel in Ghana.

3. BACKGROUND Request for access road to a fishing community at the coast Community cut off by two rivers, a stream and a lagoon/estuary Community near the confluence of two rivers Request made for three bridges Length of stretch to be traversed was 450m.

4. STUDIES CARRIED OUT Profile of the depth of peat on stretch Specific gravity of peat Plasticity tests on gravel for fill Quality of sand for fill Salt and other chemical content of water Highest level of water in lagoon Effects of tides on highest water levels type of vegetation and its effect.

5. SOME RESULTS OF THE TESTS/STUDIES Peat deeper than 4m all sections (Manual Auger Equipment used with little effort) Profile obtained at the other project site Range of S.G of peat: 1.89 to 2.05 Salt content: variable; ranges between 27.2% and 33.1% Highest level of water estimated at 1.5m above ground.

7. TEST RESULTS ON PEAT QUANTAB READING% NaCl S.G 4.833.11.89 4.630.11.90 4.833.12.05 4.427.22.00 4.65*30.88*1.96*

8. SOME RESULTS OF THE TEST ON THE GRAVEL FILL Liquid Limit (LL):Range:27 to 33 Average:30 Plastic limit (PL):Range:16 to 18 Average:17 Plasticity Index (PI):Range:12 to 15 Average:13 Maximum Dry Density : Range : 2020 to 2100 Kg/M 3 Optimum Moisture content (OMC): 7.9 to 10.7 Average:10.0

9. CBR OF GRAVEL AT DIFFERENT COMPACTION EFFORTS 100% Proctor –Range: 63 to 96 (Average : 72) 98% Proctor –Range : 42 to 64 (Average : 53) 95% Proctor –Range : 19 to 27 (Average : 24) 93% Proctor –Range : 14 to 20 (Average : 18)

10. DECISIONS TAKEN AND IMPLEMENTED Bridges and viaducts not viable A series of mass concrete pipe culverts selected Peat in channels at river culvert positions displaced with sand Gravel used to fill other sections Additional culverts to be constructed when necessary. Base of fill was broadened - 11m Only the upper layers were compacted.

11. DCP TEST RESULTS OF FILL MATERIAL DATE OF TEST: 11-12-2001 ASEMASA – ANLO BEACH EQUIPMENT : DCP WR24900 AO1 LOCATIONTHICKNESS(mm)DEPTH(mm)INSITU CBR 8+200 LHS 1.8M FROM C/C 80 120 310 390 0-80 80-120 120-510 510-900 85.5 52.9 26.5 7.6 8+250 RHS 2.0M FROM C/C 310 280 310 0-310 310-590 590-900 41.8 10.8 7.2 8+300 C/C340 560 0-340 340-900 52.9 20.6 8+400 RHS 2.4M FROM C/C 230 320 350 0-230 230-550 550-900 34.0 14.4 5.6

12. DCP TEST RESULTS OF FILL MATERIAL DATE OF TEST: 11-12-2001 ASEMASA – ANLO BEACH EQUIPMENT : DCP WR24900 AO1 LOCATIONTHICKNESS(mm)DEPTH(mm)INSITU CBR 8+400 LHS 2.0M FROM C/C 270 330 300 0-270 270-600 600-900 58.8 20.6 8.3 8+450 C/C130 360 410 0-130 130-490 490-900 52.9 21.8 7.2

15. PROBLEMS ENCOUNTERED Objection of communities to relocation of road and loss of two bridges Observation of taboo days (Tuesdays) Demand for performance of rituals Equipment got stuck at sand pits Equipment got stuck in peat Slow rate of work

16. RECOMMENDATION AND CONCLUSION The floating has performed satisfactorily over a period of 8 years. Monitoring would be continued. It is a cost effective option of providing access. Perhaps this has been successful because ADT is about 50vpd. Take the risk to float a road under similar circumstances to reduce cost and to provide access to deprived and isolated communities.