Khabour Dam, Syria
This embankment dam in north-east Syria formed part of an irrigation project for the Ministry of Irrigation (RIMA). The upstream facing of the embankment was originally intended to be hand-placed stone pitching. Practical difficulties in achieving a satisfactory end product, together with a lack of suitable rock in the vicinity, lead RIMA to look at alternatives.
Initially, machine placed rip-rap was rejected because of the greater demand for rock, with attendant extraction and transport problems.
Hesselberg Hydro was contracted to investigate the suitability of local materials for an Open Stone Asphalt (OSA) upstream facing:
- Operation of the local mixing plant was assessed
- Samples of the local aggregate were evaluated
- Acceptability of cement as an alternative to limestone filler was confirmed
- Adhesion of the local gravel with bitumen was investigated in detail
- Suitability of abundant local sand for a Lean Sand Asphalt (LSA) filter layer was confirmed
- LSA was recommended as it would increase structural stability while reducing the required thickness of OSA
Our report for RIMA provided details of mix designs, together with proposals to train local operatives in installation and quality control routines.
With an overwhelming technical and economic case, the OSA installation was accepted by the consulting engineers. However, for political reasons beyond the control of Hesselberg Hydro, the rip-rap option prevailed.