Demystifying Crushed Aggregate Sizes & Base Course Pricing in Malaysia: A Contractor’s Guide
Understanding crushed aggregate specifications and their associated costs is fundamental to successful construction projects in Malaysia, particularly for critical elements like road bases, foundations, and drainage systems. Selecting the correct aggregate size directly impacts structural integrity, compaction efficiency, drainage capacity, and ultimately project longevity and budget control.
The Crucial Role of Gradation
Aggregate gradation refers to the distribution of particle sizes within a specific material type (e.g., granite crusher run). A well-graded aggregate contains a balanced mix of coarse particles (providing strength) and finer particles (filling voids for density). Poorly graded aggregates can lead to segregation during placement, inadequate compaction resulting in settlement or instability under load (“pumping”), poor drainage leading to water retention issues (like frost heave or subgrade softening), increased permeability causing erosion within embankments or behind retaining walls.
Malaysian specifications primarily follow standards set by Jabatan Kerja Raya (JKR) – the Public Works Department – often referenced as SPJ/SPJ-Specifications. These are widely adopted across public infrastructure projects and heavily influence private sector practices.
Malaysian Crushed Aggregate Size Chart & Common Applications
Below is a detailed breakdown of commonly used crushed aggregate types in Malaysia, their standard gradations according to JKR/industry norms, primary applications based on function requirements:
1. Crusher Run / Granular Sub Base (GSB) / Road Base
Size Range: Typically 50mm down to fines/dust.
Gradation: Defined by JKR/SPJ specifications (e.g., JKR SPJ Clause 4.2). sieve sizes:
50mm: Approx 95%-100% passing
37.5mm: Approx 85%-100% passing
20mm: Approx 60%-80% passing
10mm: Approx 40%-60% passing
5mm: Approx 25%-45% passing
2.36mm (8): Approx 15%-35% passing
<75µm (200): Usually limited to max ~10%
Primary Applications: The workhorse material.
Road sub-base layer beneath asphalt/concrete pavement.
Base course for heavy-duty pavements/parking lots.
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