Rice through the Indian Agencies East to the New Mexico Line

Expansion Joints-Their Use in Arizona Concrete Highways in Salt River Valley

ABOUT 430 miles of concrete highis what causes the engineers grave conways have been built and are now being maintained by State and County forces. The greater portion of this pavement is in the Salt River Valley, Maricopa County. The land is very level and the drainage is slow, thereby causing the ground to contain much moisture at all times. Unfortunately it has to be admitted that great stretches of our highways are inundated by irrigation waters at certain times of the year. Failure to provide adequate waste ditches is the cause of this condition. This is mentioned here so that the reader will understand what the maintenance forces have to contend with, and also the effect such conditions might have on the behavior and life of the pavement.

Part of the pavement was contstruc ted without expansion joints, part with expansion joints with intervals of great distance, and some with intervals as close as twenty-five feet. Most of the pavement laid during the last two years has expansion intervals of forty feet, and the amount of expansion space allowed for forty feet was 5-8 inch. On the Phoenix-Yuma Highway, Federal Aid Project No. 71, 9.2 miles of pavement was laid with a longitudinal center joint.cern.

MAINTENANCE

There is no closed season on highway construction in Arizona. Many miles have been laid during each month of the year. However, the temperature at the time of construction does not seem to control effects of subsequent temperature action. During the summer when the temperature ranges from 90 degrees to 115 degrees Fahrenheit in the shade, the pavement is subjected to enormous compressive strain, where sufficient expansion space has not been provided. Under such conditions slip joints and heaves or buckles reaching the magni tude of blowouts occur.

SLIP JOINTS AND BLOWOUTS

The slip joints and blowouts are most dangerous to traffic and also result in additional damage to the pavement. In the case of a slip joint, the riding slab breaks adjacent to the joint and shatters under traffic, if maintenance forces fail

ARIZONA ROADS FINE, VANDERBILT DECLARES

The following excerpt from an editorial by Cornelius Vanderbilt, Jr., editor and publisher of the Illustrated Daily Herald of San Francisco and other newspapers, shows what other people think of our roads: "California and Florida may claim to have the best paved highways in this country, and justly so, but Arizona has, without a doubt, the best dirt highways in the United States, to say nothing of paved roads equally as good as any of the aforesaid States. Today we journeyed by automobile for more than 500 miles, half of the time in Caifornia and the rest of the time in Arizona. Of course, the California highways are wonderful, everyone knows that, but we had been informed almost universally before setting out that the roads in this state were miserable, bumpy, sandy, and that no time whatsoever could be made upon them. "For this reason we beg to disprove the theory and to state positively that as far as we have seen the highways of Arizona, particularly the dirt highways, are as fine, if not finer, than any highways of a similar sort anywhere in the nation today."

The above mentioned forces are present at all points along the slab during the summer months varying with horizontal and vertical curvature. Where no expansion space has been provided the pavement is distorted almost invariably upward. Where expansion has been provided, but insufficient to allow free movement, the distortion will be upward and lateral. It is well to mention another condition which will result in serious damage to the pavement, and that is the good intention of providing sufficient expansion space at proper intervals but failing to obtain it in its specified form and position. It is granted here that if the interval is right and the expansion space sufficient, little trouble will be encountered by maintenance, providing no concrete has connected under the joints or between the ends of the sections of the joint material, but to give maintenance a fair chance it must be a full joint, in true position and wide enough so as to be easily removed with ordinary working tools.To neglect the proper attention and removal of a joint which was a good and ample one to begin with places the several slabs at the mercy of the tre mendous pressure exerted by changing of temperature. This is a concentrated pressure brought on by the entering 01 dirt and sand which becomes solidified in the expansion space at points most used by traffic. This condition develops surely and the time depends upon the character of shoulder material and amount of traffic. When these accumulations or solids become sufficient in size to interfere with the free movement of the slabs the comparatively thin concrete yields to the force of expansion, exerted as it is, concentrated to a small area between the ends of the two adjoining slabs. This results in either longitudinal or corner

PAVEMENT UNDER STRAIN ARIZONA HIGHWAYS

June, 1925 Cracks and are accompanied by surface chipping on either side of the joint. Surface chipping often occurs long before the main rupture takes place, and results in raveling under heavy traffic.

It is true that some maintenance fore men work along under the impression that all that is required of them is to merely sweep clean the surface of the joints and other damaged areas and seal same with suitable material, but it is the opinion here that the majority of fore men do see farther than merely the process of patching of effects and endeavor to trace down the causes and remove them.

Once the pavement is down these causes, if present, go into effect and continue increasingly until distortion of the slab in one form or another takes place unless caught in time by maintenance-

TENTATIVE REMEDY

Undoubtedly these destructive agencies can be held to a minimum while planning for construction. This would by a very small if any additional cost at all of construction, and save many thousands of dollars which is now being spent on maintenance, and would no doubt prolong the life of the pavement several years and avoid the interruption to traffic which we now experience by the neces-

OVERFLOW BRIDGE

City of frequent repairs. The remedy appears simple and in fact is if treated as a precautionary measure with maintenance in mind at the time of planning and construction. Assuming the subgrade, drainage and shoulders are perfect, very little trouble should be experienced if proper sized expansion joints at proper intervals are specified and put in place in accordance with rigid and iron clad inspection, so that each joint will be a thorough one.

TOO MUCH PROSPERITY

"Are you crazy, Pat? Ye say ye turned down the job because the pay was too high?"

"Sure. If I ever got sick an' had to lay off, losin' so much money would worry me to death."-American Legion.

LIST OF TRAVELOGUES

Each Issue of ARIZONA HIGHWAYS will contain a travelogue, showing the condition of the highway, points of interest and hotel and garage accommodations, and other valuable information for the tourist, of the 17 main routes in the State. When completed, the Travelogues, which will be illustrated by maps and scenes along the highways, will cover all the main arteries of travel in the State, from California and Nevada on the West to New Mexico on the East and from Utah on the North to Old Mexico on the South. The list of Travelogues and the issues in which they are to appear, follows:

ARIZONA HIGHWAYS The Engineer's Log DISTRICT NO. 1 B. M. Atwood District Engineer FEDERAL AID PROJECTS UNDER CONSTRUCTION

Federal Aid Project No. 36-B. Underpass on Prescott-Jerome Highway. Railroad Company's share of construction finished. Enntire project now completed.

Federal Aid Project No. 68-B. St. Johns-Springerville Highway. Length under construction 9.6496 miles. Udall and Udall of St. Johns, Arizona, Contractors. Percentage of work complete 40 per cent.

Federal Aid Project No. 74-Winslow-Flagstaff Highway. Length of Project 20.35 miles. Construction practically completed.

Flagstaff-Angel Highway. Forest Highway on Arizona State Highway System. Length of Project 23.43 miles. 98 per cent complete.

ARIZONA STATE ROADS UNDER CONSTRUCTION

Resurfacing of the popular Prescott-Jerome Highway now under way. 17 per cent complete.

DISTRICT NO. 2 George B. Shaffer District Engineer FEDERAL AID PROJECTS UNDER CONSTRUCTION

Federal Aid Project No. 72-A Prescott-Phoenix Highway. White Spar to Yar-nell Section. Construction completed.

Federal Aid 72-B Prescott-Phoenix Highway. Yarnell to Congress Junction. Length of Project 9.038 miles under construction. Schmidt and Hitchcock, Contractors. 15 per cent complete.

Prescott-Phoenix, Prescott White Spar Section. Forest Highway on State Highway System. Length of Project 15.58 miles under construction. 86 per cent complete.

ARIZONA STATE ROADS UNDER CONSTRUCTION

Chandler-Casa Grande Highway-Non-Federal Aid. Maricopa County Section of this Highway under construction--35 per cent of work now complete.

SURVEYS

Survey has just been completed for Overpass on Federal Aid Project No. 55 -Yuma-Phoenix Highway near Wellton -eliminating grade crossing at this point.

TRAFFIC ZONING

Approximately 85 miles of paving has been marked with a five inch yellow zoning stripe. Owing to the immense increase in traffic, casualties are mounting in greater proportion, including loss of many lives. The State Highway Department has taken this step as a means of safeguarding the public traveling upon the State Highways. Upon completion of this work in District Two, Traffic Zoning will be carried on in all other Districts wherever there is paving upon the State Highway System. Although this work has barely started, a great deal of favorable comment has been received from the public.

DISTRICT NO. 3 T. S. O'Connell District Engineer FEDERAL AID PROJECTS UNDER CONSTRUCTION

Federal Aid Project No. 77-Solomonville-Duncan Highway gravel surfaced under construction. 88 per cent complete. This includes extension to original Project.

ARIZONA STATE ROADS UNDER CONSTRUCTION

Rice-Springerville Highway under construction. Widening and draining.

Apache Trail-Horse Mesa Section. Non-Federal Aid. This section will eliminate the last nine miles of Old Road to Roosevelt Dam, this being made neces-sary by the construction of Horse Mesa Dam. Work has now been completed as far as Pine Creek. Work will be start-ed in the near future on the two span concrete arch bridge over Pine Creek. This structure will have two 48 feet clear spans with over all length of 109 feet. Percentage of construction complete on this project is 25 per cent.

SURVEYS

Location Survey now being made on F. A. Project No. 87, Globe-Safford Highway. Twelve miles of this new link between Cutter and Geronimo-survey completed.

Roy White, Location Engineer, having finished survey on Horse Mesa Section, Apache Trail, has started location on the Safford State Line Highway to be known as Federal Aid Project No. 88.

The location section between Federal Aid Project No. 67 and Federal Aid Project No. 77, comprising strip of road from end of pavement at Solomonville to Junction of Clifton Highway is completed. The section from Graham-Green-lee County Line to New Mexico State line is now being surveyed.

Chief Location Engineer C. C. Smail, District Engineer, T. S. O'Connell, and John Webster, General Foreman have just completed inspection trip over Mule Creek Highway. Sections of this highway will be widened and additional drain-age structures built. Construction will commence as soon as Federal Aid Project No. 77-Solomonville-Duncan Highway is completed.

DISTRICT NO. 4 W. R. Hutchins, Acting District Engineer. FEDERAL AID PROJECTS UNDER CONSTRUCTION

Federal Aid Project No. 79-A Bisbee-Tombstone Highway. Phoenix-Tempe Stone Company, Contractors. Preliminary work and erection of plant by contractors completed. Actual construction is now under way.

Federal Aid Project No. 79-B. Benson Douglas Highway, Contractors Roger Brothers of Snowflake. Construction progress good. 37 per cent of Project completed.

Federal Aid Project No. 86-Tucson-Nogales Highway. Construction started May 26th. Contractors Downer and Fredell.

ARIZONA STATE ROADS UNDER CONSTRUCTION

Bisbee-Tombstone Paving-non Federal Aid. Length of project 10 miles. Flush Coat being placed on Asphalt pav-ing by Phoenix-Tempe Stone Co. Work being done in conjunction with construc-tion on Federal Aid Project No. 79-A.