--- title: "Rolled vs normal concrete; CC pavement construction" subject: "Transportation Engineering II" chapter: 3 key: "semester_7/transportation_engineering_ii:rolled-concrete-cc-pavement-construction" source: https://www.bctengineer.com/q/semester_7/transportation_engineering_ii/rolled-concrete-cc-pavement-construction site: BCT Engineering --- # Rolled vs normal concrete; CC pavement construction Transportation Engineering II · Chapter 3: Road Construction Technology - Asked in: 2081 Bhadra, 8 marks - Video: [BITUMINOUS ROADS AND CEMENT CONCRETE ROADS](https://www.youtube.com/watch?v=EGkuuTGewu4) — OCTAGON - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_7/transportation_engineering_ii/rolled-concrete-cc-pavement-construction - Whole chapter: https://www.bctengineer.com/md/semester_7/transportation_engineering_ii/chapter-3 ## Question Differentiate between rolled concrete and normal concrete used in road construction. Describe the construction steps of cement concrete pavement with material and quality control. ## Short answer Rolled concrete is dry zero-slump low-cement mix rolled; normal concrete is plastic slump mix vibrated. Construction: prepare subgrade/DLC, forms, dowels, place, compact, finish, cure 14 days, saw joints. PQC flexural strength about 4.5 MPa, open after 28 days. ## Answer #### Rolled concrete and normal concrete | Basis | Rolled concrete (RCC pavement) | Normal (plain) concrete | |---|---|---| | Consistency | Very dry, zero-slump mix | Plastic mix, slump 25-50 mm (or higher) | | Cement content | Low, 12-15 percent of dry mass (about 250-350 kg/m3) | High, 340-420 kg/m3 | | Water content | Low, near optimum for compaction | Higher, controlled by w/c ratio below 0.45 | | Placing | Spread by asphalt-type paver or grader | Placed in forms or by slip-form paver | | Compaction | Rolled with heavy vibratory and pneumatic rollers | Internal and surface vibrators | | Joints | Fewer, or sawn cracks at 10-15 m; no dowels | Contraction joints at 4.5 m with dowels | | Finishing and curing | Quick; roller finish, early opening to traffic (after 1-3 days) | Float and tine finish; at least 14 days of curing | | Surface | Rougher, often covered by thin bituminous surfacing | Smooth textured concrete surface | | Use | Heavy duty, low-speed roads, container yards, base for other layers | Highways, urban and rural roads | | Cost | Lower and faster | Higher | #### Construction of cement concrete pavement **Cement concrete pavement (Pavement Quality Concrete, PQC)** is built as a slab on a sub-base following IRC:15 (construction of concrete roads), IRC:58 and MoRTH Section 600; Nepal DoR specifications follow the same steps. **Materials**: ordinary Portland cement (OPC 43/53, IS:269) or PPC; fine aggregate (zone II sand); crushed stone coarse aggregate of maximum size 31.5 mm (usually 20-26.5 mm), abrasion value below 35 percent, flakiness below 25 percent; potable water; admixtures if needed; dowel bars (plain mild steel), tie bars (deformed), joint filler and sealant (hot or cold poured), curing compound. The concrete has a flexural strength of about 4.5 MPa (M40, w/c ratio below 0.45). **Construction steps** 1. **Sub-grade and sub-base**: prepare and compact the subgrade; lay a Dry Lean Concrete (DLC) or granular sub-base with a separation layer of polythene sheet (125 micron) on top. 2. **Setting out and forms**: fix steel side forms (for fixed-form paving) rigidly to line and level, or set string lines for a slip-form paver. 3. **Dowels and tie bars**: fix dowel bars on cradles/baskets at transverse joints and tie bars at the longitudinal joint before concreting (or insert them with the paver's dowel inserter). 4. **Batching and mixing**: batch aggregates and cement by weight in a batching plant and mix in a central plant (or transit mixer); slump about 25-50 mm (workability suited to the paver). 5. **Placing**: place the concrete in a uniform layer, slightly above the final level, without disturbing the dowel baskets. 6. **Compaction**: use needle vibrators along edges and joints, and a screed or surface vibrator; a slip-form paver compacts, shapes and finishes in one pass. 7. **Finishing**: float, check with a straight edge, and texture (broom or tining) for skid resistance; surface tolerance 3 mm under a 3 m straight edge. 8. **Curing**: spray a curing compound immediately, then cover with wet hessian or polythene; keep moist for at least 14 days, and protect from rain, sun and wind. 9. **Joints**: saw-cut contraction joints (about 3-5 mm wide, 1/4 to 1/3 of the slab depth) within about 6-18 hours of laying; form expansion and construction joints; seal them with sealant after cleaning. 10. **Opening**: allow traffic after the concrete attains the specified strength, generally after 28 days (light vehicles may be allowed earlier, at about 75 percent of the design strength). **Quality control**: tests on cement, aggregate and water; slump (every batch/truck); cube strength (3 cubes per 30 m3 at 7 and 28 days) and flexural beam tests; temperature of concrete (between 5 and 30 C); thickness by levels or cores (+-5 mm); level and evenness with a straight edge; checks on dowel alignment, joint depth and curing records. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. How does rolled concrete differ from normal concrete in consistency? A. Rolled concrete is a very dry, zero-slump mix; normal concrete is a plastic mix with slump 25-50 mm B. Rolled concrete is more fluid than normal concrete C. Both have the same slump D. Rolled concrete has higher cement content Answer: A. RCC is compacted by rollers, so it is a very dry mix. (Key point: Consistency) 2. How is rolled concrete compacted? A. By needle and surface vibrators B. By heavy vibratory and pneumatic rollers C. By no compaction at all D. By hand ramming only Answer: B. Normal concrete uses internal and surface vibrators. (Key point: Compaction) 3. What curing is specified for CC pavement? A. No curing needed B. Dry for 1 day C. Curing compound and wet hessian or polythene, kept moist at least 14 days (7 days minimum) D. Keep moist for 1 hour only Answer: C. Curing prevents shrinkage cracking and gives strength. (Key point: Curing) 4. How are contraction joints made in CC pavement? A. Saw-cut after 28 days B. Cut through the full depth immediately C. Not made, as concrete never cracks D. Saw-cut 3 mm wide, 1/4 to 1/3 slab depth, within 6-18 hours of laying Answer: D. Early sawing controls where shrinkage cracks form. (Key point: Joints) ## Related in Transportation Engineering II - [Construction steps of cement concrete pavement](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Acc-pavement-construction-steps) — Transportation Engineering II, chapter 3 - [Asphalt concrete construction and quality control](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Aasphalt-concrete-construction) — Transportation Engineering II, chapter 3, asked 5× - [WBM: material, equipment, procedure, quality control](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Awbm-materials-equipment-quality-control) — Transportation Engineering II, chapter 3 - [Plain CC pavement thickness by IRC, 7 m highway](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Aplain-cc-pavement-thickness-irc-7m) — Transportation Engineering II, chapter 2 - [Road construction activities; plants for bituminous and CC](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Aroad-construction-activities-plants-bituminous-cc) — Transportation Engineering II, chapter 3 - [Types of stresses in cement concrete pavement](https://www.bctengineer.com/question.md?key=semester_7%2Ftransportation_engineering_ii%3Arigid-pavement-stresses) — Transportation Engineering II, chapter 2, asked 2× ## Related in other subjects - [Quality control in urban road construction](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Aquality-control-urban-roads) — Project Engineering, chapter 4 - [Quality control of concrete at site](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Aquality-control-at-site) — Concrete Technology and Masonry Structure, chapter 5, asked 11× - [Differentiate quality control and assurance](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Aqa-vs-qc-differentiate) — Project Engineering, chapter 4 - [Quality; QA vs QC; site engineer steps](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Aquality-qa-qc-site-engineer-steps) — Project Engineering, chapter 4