Preface

vii

Chapter I

THE PURPOSE AND UTILITY OF HIGHWAYS

Transportation Problem—National in Scope—Development in Traffic—Location or Farm to Market Traffic—Farm to Farm Traffic—Inter-City Traffic—Inter-County and Inter-State Traffic—Rural Education—Rural Social Life—Good Roads and Commerce

1-12

Chapter II

HIGHWAY ADMINISTRATION

Township Administration—County Administration—State Administration—Federal Administration—Special Assessments—Zone Method of Assessing—General Taxation—Vehicle Taxes—Sinking Fund Bonds—Annuity Bonds—Serial Bonds—Comparison of Methods of Issuing Bonds—Desirability of Road Bonds

13-28

Chapter III

DRAINAGE OF ROADS

The Necessity for Drainage—Importance of Design—Surface Drainage—Run-off—Ordinary Design of Ditches—Underground Water—Tile Drains—Lying Tile—Culverts—Length of Culvert—Farm Entrance Culverts—Metal Pipe—Clay and Cement Concrete Pipe—Concrete Pipe—Endwalls for Culverts—Reinforced Concrete Box Culverts—Drop Inlet Culverts

29-41

Chapter IV

ROAD DESIGN

Necessity for Planning—Road Plans—Problems of Design—Preliminary Investigations—Road Surveys—Alignment—Intersections—Superelevation—Tractive Resistance—Rolling Resistance—Internal Resistance—Air Resistance—Effect of Trades—Energy Loss on Account of Grades—Undulating Roads—Guard Railing—Width of Roadway—Cross Section—Control of Erosion—Private Entrances—Æsthetics

42-62

Chapter V

EARTH ROADS

Variations in Soils—Variation in Rainfall—Cross Sections Elevating Grader—Maney Grader—Slip Scraper—Fresno Scraper—Elevating Grader Work—Use of Blade Grader—Costs—Maintenance—Value of Earth Roads

63-73

Chapter VI

SAND-CLAY AND GRAVEL ROADS

The Binder—Top-soil or Natural Mixtures—Sand-clay on Sandy Roads—Sand-clay on Clay or Loam—Characteristics—Natural Gravel—The Ideal Road Gravel—Permissible Size of Pebbles—Wearing Properties—Utilizing Natural Gravels—Thickness of Layer—Preparation of the Road—Trench Method—Surface Method—Maintenance

74-88

Chapter VII

BROKEN STONE ROAD SURFACES

Design—Properties of the Stone—Kinds of Rocks used for Macadam—Sizes of Stone—Earth Work—Foundation for the Macadam—Telford Foundation—Placing the Broken Stone—Rolling—Spreading Screenings—Bituminous Surfaces—Maintenance Characteristics

89-97

Chapter VIII

CEMENT CONCRETE ROADS

Destructive Agencies—Design—Concrete Materials—Fine Aggregate—Proportions—Measuring Materials—Preparation of the Earth Foundation—Placing Concrete for Two-course Road—Curing the Concrete—Expansion Joints—Reinforcing—Bituminous Coatings on Concrete Surfaces—Characteristics—Maintenance

98-105

Chapter IX

VITRIFIED BRICK ROADS

Vitrified Brick—Paving Brick—Repressed Brick—Vitrified Fiber Brick—Wire-cut-lug Brick—Tests for Quality—Other Tests—Foundation—Sand Bedding Course—Sand Mortar Bedding Course—Green Concrete Bedding Course—Bituminous Fillers—Mastic Fillers—Marginal Curb

106-115

Chapter X

BITUMINOUS ROAD MATERIALS AND THEIR USE

Classes of Bituminous Materials—Coal Tar—Water Gas Tar—Natural Asphalt—Petroleum Asphalt—Mixtures—Classification According to Consistency—Road Oils—Liquid Asphalts—Asphalt Cements—Fillers—Bitumen—Specifications—Surface Treatments—Applying the Bituminous Binder—Finishing the Surface—Patching—Penetration Macadam—Foundation—Upper or Wearing Course—Patching Characteristics—Hot Mixed Macadam—Foundation—Sizes of Stone—Mixing the Wearing Stone—Placing and Wearing Surface—Seal Coat—Characteristics—Asphaltic Concrete—Bitulithic or Warrenite—Topeka Asphaltic Concrete—Foundation—Placing the Surface—Characteristics

116-129

Chapter XI

MAINTENANCE OF HIGHWAYS

Petrol Maintenance—Gang Maintenance—Maintenance of Earth, Sand-clay, Gravel and Macadam Roads

130-134

Index

135