Saudi Arabia’s SHC 309: Material Specifications for Highway Construction

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Highway construction requires high-quality materials to ensure durability, safety, and sustainability. The Saudi Highway Code (SHC) 309 – Material Specifications sets standardized guidelines for selecting and testing construction materials used in roads, bridges, and tunnels across Saudi Arabia.

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This guide defines the engineering properties, durability requirements, and testing methods for essential materials, including asphalt, concrete, aggregates, steel, and geosynthetics. These specifications align with international standards such as AASHTO, ASTM, ISO, and SASO, ensuring compliance with global best practices.

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1. Pavement Material Standards

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1.1 Soil and Subgrade Materials

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✔ Soil Classification – Based on particle size, liquid limit, and plasticity index (AASHTO M145).
✔ Soil Stabilization – Use of quicklime and hydrated lime to improve load-bearing capacity (AASHTO M216).
✔ Moisture-Density Relations – Determines soil compaction characteristics (AASHTO T99 & T180).
✔ California Bearing Ratio (CBR) – Measures soil strength for pavement foundation (AASHTO T193).

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1.2 Aggregates

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✔ Coarse and Fine Aggregates – Specifications for gradation, angularity, and durability (AASHTO M43 & M80).
✔ Crushed Stone & Sand – Used in base and subbase layers for load distribution.
✔ Soundness & Abrasion Resistance – Ensures durability under heavy traffic loads (AASHTO T104 & T96).

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1.3 Asphalt & Asphalt Mixes

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✔ Bitumen Specifications – Standards for penetration, viscosity, and softening points (AASHTO M81, M82, & M140).
✔ Hot Mix Asphalt (HMA) Design – Ensures resistance to rutting, fatigue, and thermal cracking (AASHTO T245).
✔ Modified Binders – Use of polymers and additives to enhance asphalt performance.

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1.4 Concrete & Cement

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✔ Portland Cement – Standards for compressive strength and sulfate resistance (AASHTO M85).
✔ Concrete Mix Design – Optimized for climatic conditions and structural durability.
✔ Curing Compounds – Enhances hydration and strength development (ASTM C309).

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2. Structural Materials for Bridges & Tunnels

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2.1 Steel & Reinforcement Materials

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✔ Structural Steel – Complies with AASHTO M270 & ASTM A709 for bridges.
✔ Reinforcing Bars (Rebar) – Includes carbon steel, epoxy-coated, and corrosion-resistant alloys.
✔ Prestressed Concrete Strands – High-strength steel strands for pre-tensioned structures (AASHTO M203).

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2.2 Geosynthetics & Drainage Systems

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✔ Geotextiles & Geogrids – Used for soil stabilization and erosion control (AASHTO M288).
✔ Drainage Pipes – Standards for reinforced concrete, corrugated steel, and plastic pipes (AASHTO M170).

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3. Road Safety & Marking Materials

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3.1 Guardrails & Barriers

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✔ Crashworthy Guardrails – Designed to minimize impact severity (AASHTO M180).
✔ Concrete Barriers – Used for high-speed road safety and vehicle containment.

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3.2 Pavement Markings

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✔ Retroreflective Paints & Thermoplastics – Ensures visibility under all weather conditions (ASTM D4956).
✔ Raised Pavement Markers (RPMs) – Helps with lane guidance and road safety at night.

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4. Environmental & Sustainability Considerations

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✔ Use of Recycled Asphalt Pavement (RAP) – Reduces environmental impact.
✔ Low-Carbon Concrete Solutions – Incorporating fly ash and slag cement.
✔ Water-Efficient Construction Methods – Sustainable approaches for arid regions like Saudi Arabia.

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Conclusion

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The SHC 309 – Material Specifications provides a comprehensive framework for selecting, testing, and using construction materials in Saudi Arabia’s highway infrastructure. By adhering to these rigorous standards, engineers ensure long-lasting, high-performance, and safe roadways across the country.

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