Procedures in Modern Road Construction I. Development of Ancient Roads 1. Great civilizations throughout history enhanced road building. 2. Cross-section of ancient road 1) Three courses (bottom-up) A layer of broken stones A layer of small stones mixed with mortar A wearing course of massive stone blocks 3. Construction of ancient roads 1) a trench was excavated first so the finished surface would be at ground level; 2) a layer of small broken stones was placed at the bottom of trench; 1 Monday, May 30, 2016Monday, May 30, 2016Monday, May 30, 2016Monday, May 30, 2016

Introduction 3) the layer of small stones mixed with mortar and firmly tamped into place; 4) the wearing course of massive stone blocks was set and bedded in mortar 4. Highway, turnpike, toll road, expressway, freeway II. *Construction of modern roads 1. Project Appraisal 2. Plan the route (alignment design):Plan the route (alignment design) 1) Determination of OD, control stations, control stakes, and the like 2) Determination of width of highway, the number of driving lanes, the number and location of entrances and exits, and the essential strength of the road on the basis of the traffic volume 2 Monday, May 30, 2016

Introduction 3. Test earth foundation: 1) Strength test: density, moisture content, draining ability 2) Preparation of soil for foundation: thickness of the road layers (depth), aggregates proportion and their designated particle sizes 4. Cost estimate: how much work needs to to done (earth and rock quantities, steel, concrete, plants and equipment, overheads, salaries, and others); 5. Foundation construction: first remove the top layer of trees, plants, and organic materials; then excavate earth and/or rocks; and finally fill and compact the fillings till the roadbed meets the specifications. 6. Drainage problems: cross slope, longitudinal slope, side ditches, blind drains, culverts, inception drenches, impervious layers against capillary action and frost heave 3 Monday, May 30, 2016

Introduction 7. Earth-bound macadam surface: a bottom layer 10 to 20 cm thick of larger stones; an upper course about 8 cm thick of smaller stones 8. Types of pavements: rigid pavement (concrete) and flexible pavement (asphalt/ bitumen, tar, or heavy oils) III. Questions: 1. How is a modern road built? 2. What plants are used in a modern road construction? Name at least five. 3. What’s the difference between highway, street ， road ， way, path ， track ， trail, avenue, lane, alley, pavement/sidewalk, and boulevard?highway, street ， road ， way, path ， track ， trail, avenue, lane, alley, pavement/sidewalk, and boulevard? 4 Monday, May 30, 2016