IRC 28:1967 is the Indian Standard (IRC) for tentative specifications for the construction of cement concrete roads (over a water-bound macadam sub-base). IRC 28:1967 specifies construction of cement concrete (rigid) pavements over water-bound macadam sub-base — primarily for rural roads, village connections, and minor district roads. While superseded in spirit by the more comprehensive IRC 58 (rigid pavement design) and IRC SP 62 (low-volume concrete roads), IRC 28 remains referenced for specific rural application construction methodology. Key parameters: WBM sub-base 150-200 mm, prime-coated; concrete M25-M30 grade with w/c < 0.50; slab thickness 150-250 mm (200 mm typical for PMGSY rural); transverse contraction joints at 4-5 m with dowel bars; longitudinal joints with tie bars; water curing minimum 14 days. Concrete roads are 1.5-2× initial cost of flexible but 2-3× longer life (20-30 years vs 10-15 years for flexible). For PMGSY rural roads, concrete is often preferred due to reduced maintenance burden — rural maintenance capacity is limited. Amendment No. 1 (2010) aligned with IS 456/IRC 44 updates on concrete mix design. IRC 28 compliance + IRC 58 design + IRC SP 62 for low-volume choice gives comprehensive rigid pavement guidance for rural India.
Specifies construction methodology for cement concrete (rigid) pavements over water-bound macadam sub-base — addressing sub-base preparation, concrete mix, placement, finishing, and curing for rural and low-traffic concrete road projects.
- Status
- Current
- Usage level
- Specialized
- Domain
- Transportation — Pavement and Road Materials
- Type
- Specification
- Amendments
- Amendment No. 1 (2010) — alignment with IS 456 and IRC 44 updates on concrete mix design
Also on InfraLens for IRC 28
Practical Notes
! Rural concrete roads are 1.5-2× initial cost of flexible (₹50-70 lakh/km vs ₹25-40 lakh/km for flexible). But 2-3× longer life (20-30 years vs 10-15 for flexible).
! Rural maintenance capacity is limited — flexible pavements need periodic resurfacing (every 5-7 years) which rural areas struggle to execute. Concrete requires less maintenance (joint sealing, crack repair every 10-15 years).
! For villages with poor access to periodic maintenance: concrete pavement is often the right choice despite higher initial cost.
! Sub-base preparation is THE most commonly skipped step — rural contractors often skimp. 150 mm properly-compacted WBM is non-negotiable; without it, concrete slab fails.
! Concrete M25 minimum for PMGSY (rural); M30 for state highways. Many rural projects have M20 concrete (lower than spec) — causes premature failure.
! W/C ratio 0.50 max — often violated in rural projects. Contractor adds water on site for workability; lowers strength by 15-30%. Strictly enforce slump + W/C in contract.
! Cement content 320-360 kg/m³ — specify minimum in contract. Cheaper rural mixes often 280-300 kg/m³ which causes cracking.
! Joint spacing 4-5 m: transverse contraction joints every 4-5 m in two-way direction. Sawn with diamond blade at 1/3 depth.
! Dowel bars at transverse joints: 25 mm Fe 500D × 400 mm long at 300 mm c/c. Load transfer across joint — essential; without dowels, joint cracks propagate.
! Tie bars at longitudinal joints (for 2-lane): 12 mm Fe 500D × 500 mm long at 600 mm c/c. Prevents lane separation.
! Cube testing per IS 516: 1 cube per 25 m³ concrete; 3 cubes per set (7-day, 28-day). Sent to district lab for testing. Essential QC.
! Curing 14 days minimum water curing. Rural projects often stop at 5-7 days — insufficient, reduces strength 15-25%. Specify curing period + verify.
! Polythene curing sheeting: alternative to water curing. Cheaper and easier. Acceptable per IRC 28 Clause 9.
! Opening to traffic: 28 days for heavy traffic; light traffic after 14 days. Pre-28-day heavy traffic causes pavement damage.
! Surface finishing: bull float + broom finish for skid resistance. Flat concrete becomes slippery in rain.
! Aggregate quality per IS 383: clean, free-draining, Los Angeles abrasion < 40%. Weathered aggregate weakens concrete.
! Admixtures: plasticizers to reduce w/c without losing workability. Fly ash (up to 35%) or slag (up to 50%) replaces cement — cheaper + more durable + environmentally better.
! Cost analysis (2025 India rates): 5 km × 3.75 m × 200 mm M25 road = 3,750 m³ concrete × ₹5,500/m³ = ₹2.06 crore. Plus reinforcement, sub-base, finishing = ₹2.6 crore total, or ₹52 lakh/km.
! Joint sealing re-done every 3-5 years with bituminous hot-pour or silicone sealant. Unsealed joints admit water, erode sub-base fines.
! PMGSY rural road life: target 20-30 years with concrete. Annual maintenance budget ₹2-5 lakh/km (vs ₹8-15 lakh/km for flexible equivalent).