Towards Standardizing Construction Specifications and Design Criteria of Agricultural Roads in the GCC Countries Eng. Abdulaziz Al-Kulaib Undersecretary, Ministry of Public Works, Kuwait Eng. Fadel Al-Ajmi Assistant Undersecretary, Maintenance Division, Dr. Sayed Metwali Advisor, Maintenance Division, Dr. Ahmad H. Aljassar Associate Professor, Civil Engineering Department, Kuwait University Fourth International Gulf Conference on Roads 10-13 November 2008, Doha, Qatar

Introduction ARs to serve farming areas. Simplified design because of low traffic volumes. One main concern: to minimize cost. MPW has been constructing ARs for many years in North and South of Kuwait.

Introduction In the past: light traffic consisting of light pickup trucks and occasional heavy trucks. Therefore, did not require thick pavements. Used to be 50 mm of wearing course on top of 150 mm of prepared subgrade.

Introduction Rapid developments of farming areas in recent years resulted in heavier daily traffic (heavy trucks). This led to rapid deterioration of pavements. Need for stronger pavements was recognized.

Introduction In recent years, MPW tendered 6 contracts for construction and maintenance of AR in the Northern and Southern farming areas (total value 12 million KD = 150 million QAR). Cost of AR = 30,000 KD (390,000 QAR) per km.

Typical cross section of an AR AASHTO recommends 3.6 m Cross slope to facilitate drainage Typical cross section of an AR

Cross section Graded and compacted earth shoulders

Cross section Sunken cast in-situ concrete curb to provide lateral support and protect pavement edge

Road profile Follows the natural flat terrain in farming areas. Aesthetically pleasing, reduced construction costs, and improved safety.

Road profile

Drainage Surface runoff is drained over the crowned pavement, then down the side slopes. During winter season, vegetation grows along side slopes. This helps protect them against erosion.

Construction Subgrade soil is A-2-4 or better. Dry density 1922 kg/m3 min. CBR of 15 min. Subgrade thickness is 30 cm min., compated in two layers (each not more than 15 cm).

Construction Clearing & leveling

Construction 20 cm x 20 cm edge sunken curb

Construction Subgrade

Construction Subgrade

Construction Subgrade

Construction 4 – 5 cm bituminous wearing course 8 – 10 cm bituminous base course

Construction 4 – 5 cm bituminous wearing course 8 – 10 cm bituminous base course

Material properties (aggregates) Material Type Size Material Description Main Properties Fine Aggregate Passing # 8 sieve Natural Sand and crushed sand Sand equivalent: 30 min. for crushed sand 45 min. for natural sand - soundness loss: 15% max. (AASHTO T-104) Coarse Aggregate Retained on # 8 sieve Crushed natural stone and gravel Cubic in shape. Degree of crushing 80% min. Has at least one fractured face. Flakiness: 30% max. (BS 812). Soft and friable particles: 3% max. for base course, 2% max. for binder and surface courses. Sodium sulfate soundness loss: 12% max. Abrasion loss: 40% max for surface course, 50% max for base and binder courses (AASHTO T-96). Mineral Filler 100% passing #30 Min. 75% passing #200 Limestone, cement, or hydrated lime Free Moisture 30% max. Lime Index: 50% min. Unhydrated lime: 9% max. Carbon Dioxide: 8% max.

Material properties (bituminous mixes) Sieve % passing by weight Acceptable tolerances Base course Surface course 1 1/2" 100 - ± 5% 1" 72 -100 3/4" 60 - 89 1/2" 46 – 76 66-95 3/8" 40 - 67 54 – 88 # 4 30 - 54 37 – 70 # 8 22 – 43 26 – 52 ± 4 % # 16 15 – 36 18 – 40 # 30 10 – 28 13 – 30 # 50 6 – 22 8 – 23 # 100 4 – 14 6 – 16 # 200 2 – 8 4 – 10 Bitumen (60/70) % by weight of total aggregate 3.5 – 5 4.5 – 6.5 ± 0.4 % Marshall Stability 1600 kg min. 1800 kg min. Index of Retained Strength (AASHTO T-165), OR Net Retained Strength 90% min. 14 kg/cm2 min.

Material properties Prime coat: - Medium-curing cut back (MC-70). - Application rate 0.45 – 1.50 kg/m2. - Application temperature 60o – 80o C. - Not allowed if ambient temp. < 13o C. - Not allowed in presence of surface free water.

Material properties Tack coat: - Slow-setting emulsion. - Application rate 0.15 – 0.75 kg/m2. - Application temperature 10o – 60o C. - Not allowed if ambient temp. < 13o C.

Conclusion ARs are becoming an important element of the highway system. They provide farmers with all-weather access to markets. Traditional thin pavement design is becoming insufficient to sustain heavier traffic loads on ARs. Properties and design features may be of benefit for similar applications in the GCC.

وصلى الله وسلم وبارك على عبده ورسوله محمد . . والحمد لله رب العالمين . . jassar@kuniv.edu.kw Copy of this presentation available at www.draljassar.net