In the pre-dawn gloaming, the roadbuilding machines are just black shapes lined up beside the southbound lanes of Interstate 15. From the overpass at Miramar Way, only the light from streaking headlights betrays the angled outlines of multi-ton graders, pulverizers, rollers, trench cutters, bulldozers, and pavers. The neat lines of cars hurtling toward San Diego seem linked like iron chains anchored somewhere far away to the north.
The first sign of human life is fire. Then voices rise up in laughter and are smothered again in the rushing hiss of traffic. A small group of men who operate the asphalt paver on this freeway-widening job light an oil fire inside the screed, a long, flat, rectangular metal box low across the front of the machine. It must reach a temperature of close to 300 degrees before the paver can lay down the roadbed, otherwise the oily gravel clogs inside. About 5:15 a.m., with flames shooting out along the ground on both sides of the paver, the crew begins to drive the machine toward the closed exit ramp of Miramar Way. Another day of road building has dawned.
The 4200 feet of new highway being laid by the Daley Corporation, prime contractor on the job, is an example of what road builders call junk paving. It's a widening job that will add a sixth lane to this southbound stretch of I-15, north and south of the busy exit ramp that serves the Miramar Naval Air Station.
Small jobs like this now dominate the freeway construction business in Southern California, since virtually every major freeway was completed long ago. In San Diego County, a few medium-size jobs remain, such as completion of the seven-mile stretch of state route 52 between Tierrasanta and Santee and the nine-mile route 56 connection between I-5 and I-15 through Carmel Valley. Eventually, route 125 will extend from the Mexican border to Poway, but that’s still years in the future.
As the local freeways fill up and slow down, more road construction is not a long-term solution. "We know we can't build our way out of congestion," remarks Kyle Nelson, a Caltrans spokesman.
So road building now involves widenings, repairs, and upgrades, like high-occupancy lanes and ramp-meter installations. This means that the construction takes place in cramped areas and causes inconvenience to the motoring hordes. Crews have had to adapt by developing new building techniques and altering the composition of the basic ingredient of mass conveyance: concrete.
The freeway widening at Miramar Way was begun this past June. The job requires that the Miramar Way exit be closed during construction. Caltrans halted the job late in June at the request of the U.S. Navy, which wanted the offramp open to handle traffic heading for a Garth Brooks concert held on the Miramar base. Now that work has resumed, Caltrans again has agreed to U.S. Navy demands that this freeway exit be closed only after rush hour on Friday, July 12, and reopened the following Monday afternoon. Keeping to this schedule will require a remarkable feat of engineering and organization.
Road-building technology is not yet advanced enough to prepare a roadbed on Friday, lay down the new concrete lane on Saturday, and get the concrete to harden fast enough to open it to traffic by early Monday morning. But Caltrans believes it can open the ramp by 1:00 Monday afternoon, about 50 hours after the concrete is poured.
Normally, state specifications require that a new concrete road set up for at least 10 days before traffic is allowed on it. Although small sections of road are routinely repaired overnight and opened for traffic the next day, Sapper Construction, the concrete subcontractor on the Miramar Way job, had never been asked to attain the required "modulus of rupture" of 550 pounds per square inch in 48 hours on a section of road several hundred feet long.
Minutes are critical as the asphalt paving goes down early this Saturday morning. Asphalt forms the nonpermeable base on which the nine inches of concrete road will be laid. Daley crews worked until almost midnight Friday to grade the gravel base that forms the road's bottom layer. The base is made mostly from ground-up asphalt paving that had once been the shoulder of that section of I-15. Asphalt, which is composed of oil-coated gravel, is now designated a semi-toxic waste and is expensive to dispose of in special landfills. Many freeway contractors salvage it for roadbeds. "You're out of your mind if you don't recycle that stuff," remarks Tom Sullivan, the 59-year-old Daley superintendent, who is overseeing the job.
Sullivan is a crusty, Marlboro-puffing, self-described redneck with a sun-dried face and an American flag decal on his hard hat. He doesn't have to do much supervising, since his job foremen and the crews work together like a crack outfit, but his mock bluster and wry outlook set a certain can-do tone on the job site. When asked what exactly is going on here he barks, "We're building America!" Sullivan and several other supervisors look longingly at an unusually large number of boats being towed south on the other side of the three-foot-high sections of curved concrete slabs that form what's called a K-rail barrier, temporarily blocking the exit. Sullivan sighs about working on a Saturday and curses insincerely, "I hate this whole crew." He sweeps his eyes up and down the roadway, where men are wielding sledgehammers, digging trenches, and tinkering with heavy equipment in the pre-dawn chill. He lights another cigarette.
The asphalt paver is like a large motorized bin with a hopper into which trucks dump hot asphalt and a chute system that channels the material onto the roadbed, where the screed smooths it flat. The paver is headed for a point several hundred feet south of the exit to link up with a section of asphalt paving that was laid down before work stopped in late June. A little after 6:00 a.m., a worker drives a 12-ton roller onto the road behind the paver. It will pack down the ribbon of asphalt and prepare it for a second layer. Vibrations from the roller's drum, about five feet in diameter, send tingles through the boots and feet of everyone near the roadway. Before he begins maneuvering the roller in earnest, the driver scrambles down from his eight-foot-high perch on the machine and grabs a donut from a box on the hood of a pickup truck. Back in the roller's cab, he pulls handles and steers, clamping the donut between his teeth.
About 6:15, 29-year-old Jayne Dowda arrives. Dowda is the Caltrans resident engineer - RE in road-building lingo - in charge of the widening project. The sturdy blond transportation engineer is one of three local female Caltrans engineers, all of whom graduated together from San Diego State University in 1985. "I wanted to go into something where I could see an end product to my work," Dowda had explained earlier. "That's what makes it fun." Here she oversees a crew of six Caltrans inspectors and testers, whose job it is to enforce state road-building specifications and regulations and ensure quality control.
One of Dowda's inspectors, Rey Quiambao, bends down to stab a specially calibrated thermometer into the hot asphalt roadbed: 245 degrees. The second layer of asphalt has to be rolled out when this bottom layer drops to about 180 degrees. When the asphalt is laid and compacted, it will provide a hard base for the concrete freeway and will also channel off the water that trickles down through cracks in the concrete and direct it toward drainpipes buried alongside the road.
Thirty-four-year-old Mike Sapper, who will supervise the concrete paving, arrives at about 6:30. He and his two brothers and their father, along with a few other family members, have paved concrete roads throughout San Diego County and the western U.S. Currently, they're working on a major paving job on the Harbor Freeway in Los Angeles, near Watts. Mike points out the evidence of that job on the company's slipform (concrete) paver, a massive piece of equipment - 9 feet high, about 12 wide — that sits a few feet from the asphalt roadbed. "This was covered with graffiti, but we removed most of it already," he says. The machine still bears plenty of spray-painted squiggles and odd arrangements of letters. One recurrent graffito reads "OSOK." A member of Sapper's crew found out what it meant: One Shot, One Kill.
Sapper says his company had to hire a security guard in L.A. to keep kids from throwing chunks of concrete from an overpass onto his crew. A crane operator on that job was shot in the leg. Some workers wear flak jackets, some carry knives in their boots, and a few carry concealed guns. Somebody set ablaze one of the company's fuel trucks and punched holes in the radiators of his front-end loaders. "The sad part is, the footprints were about this big," Sapper declares, holding his index fingers about five inches apart.
This San Diego job has its own set of pressures and unknowns because of the tight deadline. The concrete on the offramp will have to set up so quickly and reach such a high strength that a special mix will be required. Plus, Sapper Construction usually batches its own concrete in the company's portable plant, which is moved into place near a job site. But on this job, because of the lack of space available beside I-15, the concrete has been subcontracted from the Mission Valley plant operated by CalMat, and this ready-mix concrete will be trucked in. The arrival times will be critical because there is little margin for error in the quick-drying concrete mix. The first truck is scheduled to be here at 8:00 a.m. But just past 7:00, the second asphalt layer still isn't finished, and Mike goes to the phone in his pickup truck to delay the first concrete delivery until 8:45.
One of his concerns is the high temperature of the asphalt base. If it's too hot when the concrete is poured, it will draw the water in the concrete downward, causing the new roadway to hydrate too quickly and to crack. Concrete, which is the second most-used material on the planet after water, doesn't dry, it hardens through a chemical reaction called hydration. The water doesn't evaporate from the concrete but combines chemically with other ingredients to form a solid mass. To speed up that process for this job, calcium chloride will be added to the mix, along with a higher amount of-Portland cement.
A week ago, Sapper prepared a test batch of this unusual mixture, and Caltrans testers formed beams from the material. Forty-eight hours later, they broke the beams with a hydraulic jack, but the samples had not reached the required strength of 550 pounds per square inch. They cut back the calcium chloride from two percent of the mixture to one and one-half percent and increased the cement from seven and one-half sacks to eight sacks per cubic yard of concrete. Normal freeway concrete uses six sacks of cement per cubic yard. The other ingredients — rocks not bigger than one and one-half inches long and washed sand — remained the same. This new recipe wasn't tested; Caltrans and the Sappers are almost certain it will work. Today, Caltrans will cast new beams at the work site as the job progresses, which is standard practice, then break and test them Monday morning. The test results will determine whether they can open the ramp on schedule or must leave it closed and miss the Navy's deadline.
At about 8:00 a.m., Sapper's crew starts up the concrete paver. The $350,000 machine rolls on four tanklike tracks, each independently steerable. It looks like the platform that moves rockets onto their launch pads or someone's idea of a machine for a futuristic mining operation on the moon. Ponderous but spindly, massive yet delicate, the lumbering behemoth is capable of acute precision. At 33 tons, it weighs about as much as one of Miramar's F-14s.
The operator, Gregory Arizpe — Goyo to his crew — has run the machine for 11 years. He rides on top and flips switches as the rest of the crew swarms around it like spiders. The tracks barely fit on the existing roadbed inside the concrete K-rails. Antennae-like sensors protruding from the sides of the machine are moved into position so that they lightly touch an orange stringline that has been rigged along the K-rail. This will control both the paver's direction and the thickness of the new concrete road. Another stringline runs along the outside edge of the asphalt base at the road's shoulder; sensing antennae on the outside edge of the paver will brush along this line. Tbgether, the two long pieces of string will guide the hulking machine. Goyo doesn't have to steer it.
Now a small army of men is moving in concert. Some pump water into a tank on the paver, some are under the machine, wielding wrenches. Others spray cooling water on the compacted asphalt base or cut a trench for one of the drains that will draw water from beneath the roadbed. Jayne Dowda and Mike Sapper discuss the problem of moving the concrete mixing trucks onto the narrow roadbed while it's still hot and may be vulnerable to the weight of the trucks. If there's a hangup in coordination - such as a breakdown in the paving machine - the concrete mixers might have to be sent back to the CalMat plant to dump their loads. Caltrans specifications limit the ready-mix to 90 minutes in the truck or 250 revolutions of the mixing drum, whichever comes first.
Tom Sullivan stands aside and marvels at the precision work, which looks like a kind of blue-collar ballet. When he's asked what his task is, he flashes a wry grin, takes a long drag on his Marlboro, and remarks, "Somebody's gotta be the orchestra director."
As a rubber-tired roller drives up and down the asphalt, spraying water and kicking up white steam, Dave Sapper, Mike's older brother, bends down and lays his palm on the black roadbed. Too hot. Dave usually handles the business side of the operation, but the oddity of this job has brought him out to the job site. "You usually have several days to let the asphalt cool," he observes. '"The concrete we lay down heats up too, as it sets, and that combined with the hot asphalt could be a problem.” But the Sappers have no choice. To stand any chance of reopening the ramp Monday, the concrete has to go down now. The Sapper brothers look up at the low, gray cloud deck and give thanks. The last thing they need is a hot sun.
The first concrete truck arrives at 9:00 a.m. Chunky silver mud slides down the truck's chute and forms small hills on the asphalt in front of the paver. The mixing barrel spins fast one way, then reverses and spins the other way, while men in rubber boots shovel the thick mass back toward the paver. The concrete looks oozy and wet, but it takes longer than usual to get it out of the mixing barrel. Over the screaming engine of the concrete truck, Mike Sapper observes that the extra thickness of the mix reflects its low "slump," which is a measure of concrete's workability.
Because of the quick-set nature of this batch, Caltrans required a relatively low slump of two inches. Slump is tested by packing the concrete into a funnel-shaped metal container, similar to the orange cones used as road barriers. When the concrete is sufficiently packed, the cone is lifted off. The resulting volcano-shaped concrete then settles — slumps — at the top. Normal roadbuilding concrete settles five or six inches; but because of the extra cement in this batch, there is very little slump.
At 9:12 the paver starts inching forward. A huge steel auger, like a drill bit mounted horizontally across the front of the paver, starts spinning, spreading the wet concrete evenly across the 12-foot-wide roadbed. Just behind the auger is an array of vibrating tubes. Goyo has set these vibrators at 6000 rpm. They settle and compact the raw concrete before it slips under the paver's tamper bar and 12-foot-wide steel plate. Out behind the plate comes a smooth highway, about nine inches thick. Since this is a far-right-hand lane, the concrete has to be that thick to withstand the weight of trucks. The left-hand lanes of freeways are only about seven inches thick.
Behind the concrete paver, the finishing crew wields long-handled smoothers and straight-bladed shovels. But a problem is immediately evident. The nine-inch vertical edge of the new concrete roadway isn't staying straight, it's collapsing. Mike Sapper says the concrete has too much water in it. He looks at a yellow form the concrete-truck driver brought with him that lists the exact amounts of the various ingredients that were loaded into the truck. It shows that 286 gallons of water were used for a load of about nine and one-half cubic yards of concrete.
Dick Miller, in charge of quality control for CalMat, pushes his boot into a pile of freshly dumped concrete and sends an assistant to radio the plant to reduce the water content. Miiler, who wears a magnificent handlebar mustache, explains that two gallons of water per cubic yard of concrete is withheld at the plant until after the slump test, to give the Caltrans inspector at the plant some latitude in fine-tuning the mix. After the slump test, Miller says the inspector added five gallons of water to each truck, which has turned out to be too much. "For paving, the drier your concrete, the better," Miller remarks.
To make the thick, raw concrete easier to work with, CalMat added air to form tiny bubbles in the mix. In an earlier interview at the company's Mission Valley gravel pit, off Friars Road just west of Stadium Way, Miller explained that this special mix would be difficult to work with because of its low water content — 36 gallons per cubic yard. The addition of an air-entraining agent, which increases durability by creating tiny air pockets through which water can move during successive weather-induced heating and cooling, also adds plasticity to the raw concrete. Miller drew an analogy to the addition of sugar in whipping cream, which not only sweetens the whipped cream but also acts as an air-entraining agent that provides the whipped cream's body. In concrete the agent is neutralized vinsol resins, which are the squeezings from wood pulp.
According to Miller, the ancient Romans discovered the advantages of adding air to concrete, and the result is that some of their aqueducts are still standing, as are major portions of the Colosseum, constructed in about A.D. 75. "They found that their concrete lasted longer if they added animal blood to it. The blood acted as an air-entraining agent, though they probably didn't know that.”
Outside Miller's office was a 103-ton D-ll Cat powered by an 817-horsepower diesel engine, the largest earth-moving machine Caterpillar makes. The Cat's blade alone is 12 feet wide and 6 feet high. It shoved tons of rock and sand over a steep precipice. "The philosophy of concrete is to simulate granite," Miller explained. Cement and water act as a gluing agent for different-sized rocks, from small stones to gravel to sand. The cement, which is still a substance of some mystery to researchers, comes from the city of Mojave. It is a powdery, kiln-fired mixture of limestone, sand, clay, and iron. Advances are still being made in the basic makeup of cement, which is helping to create super-strength concretes of 6000 psi. "When I first started in this business, 4000 psi. was high strength, and nobody was even trying 6000. Now 4000 is everyday strength," Miller marveled.
The crushed rock - aggregate is the technical term - in most locally produced concrete comes from a formation that underlies much of the southern part of the county, called Poway Conglomerate. It consists of baseball- and football-sized volcanic cobbles deposited in a sandstone layer 150 feet thick about 43 million years ago — just as the dinosaurs were disappearing. The sand comes from a mine in Sloane Canyon, near Singing Hills, along the banks of the Sweetwater River. Beach sand cannot be used in concrete because the grains are too fine and uniform in size; it's also expensive to wash off the salt. River-sand grains are more variable in size and bind better to the cement. "If we didn't have sand, we wouldn't have cities," Miller observed.
By 10:00 a.m., the concrete trucks are dumping much drier mud than the original loads, and Mike and Dave Sapper are surprised and relieved that the material isn't acting any differently from regular six-sack concrete. The Sapper family patriarch, Gene, who is 61 and semi-retired from the family business, pulls up in a silver Mercedes with a couple of dozen donuts for the crew. He's wearing bright red shorts.
The eldest Sapper checks out the raw concrete being dumped from the mixing trucks, which is now the consistency of extra-chunky cottage cheese. Behind the paver he sees that the edge of the new road is holding straight and vertical. Gene remarks that, having started in the business of building curbs and gutters in 1962, then switching to road building in 1978, "I can't drive a mile in this town without running into a job we did." Evoking the spirit of competition among local concrete honchos, he adds, "Wherever the concrete is smooth, that's Sapper concrete."
Sapper says his crew has had to travel all over the western U.S. to perform large-scale paving jobs. The job in Watts entails widening the road in order to put a double-deck onto it, and another job the Sappers have a piece of is on the new Century Freeway, which will eventually extend from the L.A. airport to Santa Ana. "That's the last one they'll build in L.A.," Gene explains, "and it's costing $3000 an inch because of all the people that have to be moved."
This Miramar Way job has a budget of $800,000, which will be divided among six different contractors. On major freeway paving jobs, when miles of concrete are being laid four lanes at a time, the Sapper company receives between $150,000 and $200,000 a day for building about 3000 yards of road. "When it's going right, all these finishers should be standing around doing nothing," Gene says, indicating half a dozen men who are smoothing the concrete behind the paver. When other contractors see the paving operation running well, it looks easy. "A lot of guys see our operation and say, 'Gee, why should I subcontract out this job? We can do that,' " relates Gene's son Dave. "So they buy some of the equipment - the bigger paver alone costs half a million dollars - and find that it only looks easy, and then they go broke."
Gene says several San Diego contractors have gone broke for another reason: the state requirement that about 20 percent of the work go to DBEs — disadvantaged business enterprises, which are owned by minorities or women. "With the recession, a lot of good minority-owned companies were drawn to public works like this because of the lack of work in the private sector," Gene explains. "And the state needed them. But the businesses weren't familiar with all the specifications and procedures and the paperwork. This was all new to them. I know of several companies, good companies, right here in San Diego that went belly-up after getting some of these jobs. It's a real shame that a program that was supposed to help them actually ended up hurting them.”
The Sappers have an advantage in this area. Gene was born in Guatemala to a German father and Guatemalan mother and is currently the Guatemalan consul in San Diego. This qualifies Sapper as a minority-owned business. Plus, most of the Sapper crew of about 20 men are Latino.
The paver eases forward with Goyo at the controls. Flapping on either side of him are two flags — the California Bear and the Stars and Stripes — which are always raised when the paver is in use. But two other flags that usually fly above the rear tracks of the paver are missing. Since they were working in gang territory in Los Angeles, the Sappers were advised to take down the Guatemalan flag and the Mexican flag. "The red in the Mexican flag is the color of the Bloods,” Gene explains, "and the blue in the Guatemalan flag is the Crips. You don't dare wear those colors up there. One or the other gang will attack you." The crew would normally be flying those flags here in San Diego, but somebody tore off the flanges where the flagpoles are mounted.
Close to 11:00 a.m., the concrete paver rolls slowly past Daley's asphalt paver, which sits out of the way to be used later to lay down the road's shoulder. "We're always competing against the asphalt industry," Gene comments. "One of the arguments is, concrete takes too long to set up. But this fast-track paving like we're doing here is coming along quick."
The war between asphalt and concrete for road building has see-sawed since the end of World War II. Before then, roads like Old Highway 80, east of San Diego, were paved with concrete; but after the war, asphalt paving was perfected. Asphalt is cheaper to lay down, which is why most surface streets in the cities are paved with it. But as the price of oil climbed, so did the price of asphalt; two years ago, the price of asphalt topped $45 a ton. Concrete paving was about $75 a cubic yard, which is equivalent to about two tons of asphalt. For a time, asphalt and concrete were competitive in price; but now, with the price of oil back down, asphalt sells for about $25 a ton.
But asphalt's main drawback is that it requires more maintenance than concrete. Potholes don't develop easily in a concrete road. The biggest problems with concrete are caused by the deterioration of steel reinforcing bars used to strengthen bridges and overpasses. This has caused a fiscal catastrophe back East, where ice and salt and heat besiege the roadways. Locally, concrete's problems are related to San Diego's tremendous growth, which outpaced the traffic predictions of Caltrans engineers. Sections of certain roads, such as 163 from Quince Street to I-8, have had to be resurfaced (with less-expensive asphalt) because the original concrete road was designed for much lighter vehicles and lower traffic volumes.
While most state highways are made from concrete, large stretches of certain roads have recently been paved with asphalt, including new sections of route 67 north of Poway and route 76 near Bonsall. Both of those areas carry fairly light traffic; and route 76 will eventually become a major freeway, so Caltrans engineers figure that it would not make economic sense now to put in concrete, which is difficult to tear out. Another highway that has been paved with a conspicuously long section of asphalt is route 52 between 805 and I-15. An old landfill underlies that stretch of road, and as it settles, the roadbed moves. Asphalt is more flexible than concrete and is easier to repair when the settling damages the road.
Building a concrete road takes longer and requires more equipment than laying down asphalt. As the work progresses on the Miramar Way job, more machines are pressed into service. About 20 yards behind the paver is another strange-looking device called the curing machine. It looks like a giant comb on wheels. It sprays a white curing compound on the soft concrete, and it also gouges grooves in the road surface with its long tines. The curing compound seals the concrete so it doesn't hydrate too quickly, which would cause excessive cracking. The grooves, which are about three-eighths of an inch deep, provide traction for vehicle tires.
In a few hours, after the concrete has set up enough to walk on, a crew with a diamond-bladed saw will slice down two and one-half inches into the road, creating what are called weakened plane joints. Engineers know there isn't a way to stop concrete from cracking, so they cut these joints in the road to create weak spots that become the cracks. The slices are made at a slight angle across the roadway so a vehicle's tires don't hit them simultaneously. The slices are spaced unevenly, in repeated sets at intervals of 12, 15,13, and 14 feet, to avoid creating a rhythmic bouncing or vibration in vehicles as they cross the cracks. The lore is, when these cuts were first made, they were spaced at regular intervals, and heavy Buicks would drive over them at 60 miles an hour and generate a rhythmic vibration that would eventually put the driver to sleep or thrum the cars to pieces.
By 11:30 the last couple of concrete trucks are flushing their loads in front of the paver. The finishing crew smooths and wipes the road, the curing machine brings up the rear, and the Caltrans testers set up their concrete beams for the break test on Monday morning. It all looks rather easy and fun. ''You ought to try doing it in the desert," chuckles inspector Rey Quiambao.
At 8:00 a.m. Monday, a steady pace is already set, with the concrete trucks lined up along the roadside, the concrete paver inching forward, and the pipe crews laying French drains wrapped in semi-permeable cloth in a trench beside the new road. This cloth will filter out dirt and prevent the perforated pipe from clogging. The concrete is now using the standard six sacks of cement per cubic yard, since this stretch of new lane, to the south of the Miramar Way exit ramp, doesn't have to handle vehicle traffic until July 27, 12 days from now. Goyo has set the paver's vibrators at 8000 rpm, 2000 higher than Saturday, when the concrete contained more water. Navy jets performing touch-and-go landings whoosh and whine overhead, and nobody's towing a boat in the thick stream of rush-hour traffic going south on 1-15.
Jayne Dowda confers with her beam tester, Bill Caughlin, who will perform the break test on Saturday's beams to determine whether the Miramar Way ramp can be opened before 1:00 p.m. today. Caughlin cannot leave for the Caltrans yard in Chula Vista, where the beams are setting up in a pile of moist sand, until after he forms today's test beams. (The state requires that a set of test beams be made for each day's section of new road.) Caughlin has to wait for one particular concrete truck, which is here but stuck in the middle of a long line of mixers. That truck, number 814, is the one that had a precise mixture of ingredients measured by a computer at CalMat's plant. Caughlin cannot make his three test beams until 814's turn comes to dump its load in front of the paving machine.
Finally, at 9:25, Caughlin fills a wheelbarrow from the belly of the designated truck. He places a thermometer in the gray mix: 70 degrees. It will heat up to close to 100 degrees as it sets. He takes a 30-pound ball from a wooden box and uses the attached handle to set the ball onto the wet concrete for a slump test. A small shaft suspended from the handle measures how deep the ball settles into the mix. It goes down about an inch — just right. Caughlin and a helper then fill two steel buckets of known volume and weight with the wet concrete. These are weighed on a scale to within 5/100ths of a pound. This is a test of cement content. The computer batching gave precise measures of the weight of the aggregate and the water at the time the concrete was mixed; a Caltrans chart will reveal how much cement is in the mix, depending on the weight of the filled buckets.
A final test checks air content in the concrete. A lid with a pressure gauge is locked over the top of one of the buckets. The pressure gauge reading shows that the concrete contains about three percent air, perfect for West Coast weather conditions.
In the East, where freezing and thawing occur, the air content is closer to six percent, providing more air pockets for water to expand and contract.
Finally, Caughlin fills three steel forms 34 inches long and 6 inches square. These will form the day's test beams. Another worker stabs the mix exactly 70 times with a steel rod before placing a lid over the forms. At about 10:30, Dowda gives Caughlin the number for the cellular phone in Tbm Sullivan's truck so he can call in the beam break results. Caughlin jumps in his orange Caltrans pickup and dashes down to the test trailer in Chula Vista, off Highland Avenue, to break Saturday's beams.
Behind the green Caltrans trailer is a small forest of broken concrete shafts. "I used a bunch of these to build a fence around my dad's swimming pool," Caughlin says as he digs a beam out of a pile of sand. He was the beam tester on the high-occupancy lanes built in 1989 on 1-15, and he had to break six a day.
Caughlin slides Saturday's quick-set beam into a steel cradle suspended from a narrow bench that has a hydraulic jack bolted beneath it. He centers the jack's plunger on the beam. As he increases the pressure of the jack, he watches the needle of the pressure gauge and reads the numbers out loud. "Three thousand, 31, 32, 33, 34, 35, 36, 37 -'' Pow! Caughlin laughs involuntarily at the startling snap of solid concrete. He stands the two sections of broken beam on end and notes with approval that some of the stones inside have broken in half instead of simply pulling free of the gray mass.
On major road jobs, the beams are tested at 7 days, 14 days, and 28 days after being formed. Each interval has a certain strength requirement. "But concrete reaches the vast percentage of its strength in the first 36 hours," Caughlin explains. The beam he just broke is 49 V2 hours old. He measures the sides of the beam — six inches by six and one-half inches — and checks a chart to obtain the corrected load. Although it broke at 3700 pounds of pressure, the corrected load is 3600 pounds, and he cross-checks this on another chart that interprets flex strength. It comes out to 719.7001 pounds per square inch, well over the 550 psi required before traffic can be allowed on it. He heads into the trailer to call Jayne Dowda at the job site so she can order the K-rail removed from across the Miramar Way offramp. It's 11:30 a.m.; they've beaten the deadline by 90 minutes.
The final test of any new section of freeway is for smoothness. Caltrans specifies that an accumulated total of no more than seven inches of bumps is permissible in a one-mile strip of road. To measure this takes a machine called the profileograph.
At 6:30 a.m. the Friday following the offramp reopening, a Daley employee, Daryl Granbois, unloads the company's profileograph from the back of a trailer. He carefully places the spindly contraption on the new lane added south of the Miramar Way exit, which will be closed to traffic for another week, and checks to make sure everything is in place on the $28,000 machine.
The device consists of a narrow aluminum frame 25 feet long that rests on casters. A fat bicycle tire is mounted midpoint in the frame. A computer console with a paper readout is mounted above the tire, near a small steering wheel. From a distance, the thing could be a high-tech go-kart with a heart monitor. Granbois pushes the profileograph for a measured one-tenth of a mile to calibrate it, then rolls it back to the start of the new roadway. Some of the weakened plane joints have already cracked through to the asphalt base. As he pushes what looks like a big kid's toy, Granbois jokes with the only other worker present, Caltrans inspector Rey Quiambao, who is here to make sure the profileograph is operated to state standards.
When he's ready to begin, Granbois uses a chain suspended on an arm sticking out from the profileograph to line up the bicycle tire three feet from the edge of the road. This is about where the passenger-side wheels of vehicles will be rolling. On the computer's digital display panel, he punches in the date (July 19), the location (1-15), the pavement type (PCC — Portland cement concrete), and his starting point. "Bump locator — on," he calls out. "Bottom bump — on.” This second locator will measure depressions in the road. He's finally ready for his first pass. When he's covered the 4000 feet down the passenger side of the lane, he'll be towed back and realign for another pass down the driver's side, three feet from the K-rails that still separate the rumbling traffic from the ribbon of virgin concrete. At 6:45, the profileograph starts rolling.
As he pushes on the steering wheel, Granbois explains that the roughness of the concrete surface, which has been grooved and feels like sandpaper, is automatically filtered out by the computer. Any bump or depression greater than three-tenths of an inch is a "must-grind" that's marked on the paper printout. These areas will have to be smoothed out later using a grinding machine that rents for $4000 a day. "It's definitely in our economic interest to make the smoothest road we can," Dave Sapper had remarked earlier.
The printout describes a single line that squig-gles up and down like a fibrillating electrocardiogram. In the first 1170 feet of road, the readout notes two must-grinds, both of them bumps. Any depressions that appear will also have to be dealt with by grinding to smooth them into the rest of the road, since it’s not possible to patch concrete. After 2250 feet, the machine notes six must-grinds. "Not bad," Granbois remarks. Rey Quiambao walks alongside, recording on a small scratch pad the locations of the bumps and gouges. When the process is completed, the machine identified about two dozen spots that need to be smoothed out. This is considered a lower than average number of must-grinds. A smooth road.
Looking down from the Miramar Way overpass onto the new lane next to the existing freeway, the white ribbon seems a pure and unsullied sash stretched out carefully beside a partied-out cummerbund. After all the fretting and ingenuity and physical skill and organization invested in the new lane, it seems shameful to dirty it up with mere cars and tractor-trailer rigs. Made from rocks that dinosaurs might have trod, glued together in a chemical process that was discovered by the Romans but is still advancing, the road should be used by something more majestic. Caltrans ought to consider posting a sign at the southbound - Miramar Way offramp, at least until the new-lane opens for vehicle traffic: Chariots Only Next 3/4 Mile.