IRC 111 : 2009Specifications for Dense Graded Bituminous Mixes

IRC 111:2009 is the Indian Standard (IRC) for specifications for dense graded bituminous mixes. IRC 111:2009 is the Indian specification for designing and accepting dense graded bituminous mixes — DBM (binder course) and BC (wearing course) — that surface almost every Indian highway. It mandates the Marshall method of mix design: aggregate is blended to a specified dense gradation, bitumen is added at several contents, briquettes are compacted with 75 blows per face and tested at 60 °C for Marshall stability and flow, and the optimum binder content is fixed at the air-void target. Acceptance is volumetric — air voids 3–5%, minimum VMA by aggregate size, VFB 65–75%, Marshall stability ≥ 9 kN, flow 2–4 mm and minimum retained stability after water immersion. MoRTH Specifications Section 500 (Clauses 505/507) adopts these requirements, so IRC 111 is the de-facto governing mix-design code for DBM and BC.

Specifies the materials, mix design and construction requirements for dense graded bituminous mixes — Dense Bituminous Macadam (DBM) and Bituminous Concrete (BC) — used as binder and wearing courses in flexible pavements. Covers aggregate quality and gradation, binder selection, Marshall method of mix design, volumetric and strength acceptance criteria (Marshall stability, flow, air voids, VMA, VFB, retained stability), and laying/compaction control. It is the technical basis adopted by MoRTH Specifications Section 500 for DBM and BC.