 What we're working on today, we'll be looking at is on the sharp section, the SPS-4 test road in Kansas. Serial number for this particular section is 2084. We had two existing test sections located here and are now looking at some surface deterioration that's taken place and will go through the process of the rehabilitation of this surface. This particular pavement when it was constructed in 1985, had dowel baskets for joints every 30 feet. The shoulders and mainline were all poured simultaneously so we had 40 feet of pavement, 24 foot lanes plus a 6 foot and 10 foot shoulder all poured simultaneously. The 30 foot originally planned joints do not appear to be moving correctly. It's quite possible that they're frozen up and so each of the 30 foot panels has cracks fairly close to the middle making 15 foot panels out of it. These mid panel cracks also tend to line up with the 15 foot spacing joints that were sawed on both the inside and outside shoulder. You can see here some of the spalling and deterioration that's taken place at one of the joints when I get the screen back on it. You can see that there is some vertical motion taking place. Now this is at one of the joints that has formed in the mid panel and so we'll go through today the process of inserting dowel bars to eliminate the vertical motion in these joints, allow horizontal motion and hopefully rehabilitate the surface so that it becomes smoother. Here's the serial number of one of the sharp test sections. You can see as we slowly drive down the road here there is evidence of vertical faulting as shown by the shadow cast by the low sun angle this morning at the mid panel cracks. We re-established or established two new test sections to go in conjunction with the SPS section here, one of which we had the dowel insertion and down and ground the surface but stopped at that point. We did not re-saw the transverse cracks and attempt to seal them. The other test section we did go ahead and re-saw the transverse crack and attempt to seal it and you'll see all of that as we go through the process of the dowel bar slot cutting and insertion. Here we see the sawing equipment that is the first step of creating the slots for the dowel bar insertion. This particular piece of equipment has two sawing mandrels on it and each mandrel has six saw blades spaced in pairs giving a slot about two inches wide and one foot spacing between each pair of saw blades which gives us parallel slots. The red mark you see on the pavement simply marks the location of the transverse crack that they are attempting to saw on. The two sawing heads are individually controllable so that they do not have to be directly across from each other in case there is some meandering to the transverse crack which usually is the case. The depth finder that you see on the dolly wheel that we keep zooming in close to shows how deep the saw is going into the pavement and they saw these slots in three passes generally. The first passes to a depth of two inches then they'll lower the blades two more inches into the pavement and saw back the other direction and once they reach the starting point and they drop the blade the final inch to inch and a half making a total of about five and a half inch depth and they make the final cut going in the forward direction again. So in three passes then they have sawed all of the slots that will attempt to zoom in close and see the blades. It's kind of hard to see up underneath the machine there but you'll notice that there are some pairs of diamond cutting blades with about a two inch space between them and in just a second we'll pull the machine away and you'll be able to see the resulting slots on the pavement. Here's the resulting slots for one wheel path. There are three slots in each wheel path approximately two inches wide 24 to 30 inches long on the surface and the transverse crack hopefully is fairly close to the middle of each of those slots and again you'll see the red mark on the pavement which helps the equipment operator locate the crack when he's sawing the slots. The next step is to chisel out the material in each slot and here we use lightweight chipping hammers to chisel a material trying to make the pieces as large as possible and do minimal damage to the concrete on either side of the slot. They are now doing just light chiseling to clean the rubble out of the bottom of the slot and then using compressed air to blow the loose pieces out of the slot. It's then loaded into a front end loader simply to get it off of the lane scooping it up by shovel and loading it into a dump truck to haul away. The next step is to clean the slot thoroughly prior to putting the dowel in place and putting the grout in using sandblasting here to clean the sidewalls of the slot as well as the bottom and to blow the debris away from the surface. Cleaned out slots with the sides having been sandblasted to remove any loose deposits from the sawing and slot cutting action so that we have a nice clean dry firm surface for the grout cement which will be put in with the dowel to adhere to. We look closely at the sidewall of the slot and you can see the vertical crack which is the transverse crack formed by nature that has run down through the slot. This is looking down in the slot at the bottom. It's chipped out fairly smooth and I'd have to worry too much about this because the dowels do sit on chairs which holds them up off the bottom about a half inch. You can see by the ruler here that the slots have cut about five and a half to five and three quarters of an inch deep. Here we happen to be cutting right beside the reinforcing steel that's in this pavement. It's a 6x6 mesh and you'll notice as we zoom in on it that the wire in the reinforcing steel is actually broken at the point where the vertical crack goes down through the pavement indicating that there was enough stress at this location and this is probably characteristic throughout the site that it actually severed the steel. Thus you've lost the load transfer and motion inhibitors and that's why we're installing the dowels to try and re-establish that load transfer. Here you can see one where the steel was actually cut by the saw blade and was snagged and pulled out a little bit. Once the hole has been prepared in this manner then we are ready to lay out the dowels and install them get ready to put the grout in place to hold them in. Here you see the three dowels sitting in place. The light green color gives the epoxy coating on the dowels. They're inch and a half diameter and 18 inches long. The red sleeve that you see on one end of each dowel is a plastic tubing that is used as the bond breaker. The plastic tubing would become adhered in the concrete and the dowel would allow motion inside that plastic tubing thus allowing for the expansion and contraction of the concrete pavement. You see the chairs that each of these dowel bars are sitting on which holds them up off the bottom of the slot approximately a half inch and also keeps them centered in the slot that's been cut. It's a two inch slot we're putting in an inch and a half dowel bar. Set the dowel bar down in the slot and in positioning the dowel bar you would want the sleeve pushed up onto the dowel bar and have the joint between the red and the green approximately at the location of the transverse crack. The next step in the insertion process is to deposit the concrete slurry in the slots. We use a mixer that just drives long, dumps a deposited amount spread around by shovels to make sure that you've got enough to fill all the slots. Any large chunks are removed. Then they come along with a vibrator as you'll see here in just a second when he stops at the next hole. He uses an electric vibrator to briefly consolidate the material to make sure that it is thoroughly settled down in the hole around the rebar and also that the hole is uniformly filled and that the air has been pumped out of it. Residue is then scooped off of the shovel. Squeegee is used to finish the process of smoothing off the surface of each of the dowels. Not a whole lot of time was spent doing this because diamond grinding was going to follow behind this so the surface did not have to be finished very smoothly. Once the consolidation and smoothing off had been completed, a light spray of curing compound was sprayed on each of the three slots to help slow down the evaporation of water from the concrete grout. The next step was to diamond grind the entire surface. It was elected to diamond grind the entire length and width of each lane as opposed to trying to spot grind at the locations where the repairs have been made. Here you can see the slots that have been filled prior to grinding and in the outside wheel path you can see where the grinding has taken place and the slots of war less disappeared. The grinding was done in three passes, four feet in each pass, three passes thus making a full 12 foot lane and as I said the entire length and width of the driving lane was lightly ground just enough to take out the irregularities of the vertical faulting that had taken place at the joints. The slurry residue, water and grinding material that the machines generated was simply pumped over to the side of the road and dumped on the shoulder. The texture that's left by the grinding operation as you can see is longitudinal grooving so to speak. The series of diamond blades used in the grinding are approximately eight to an inch wide each with approximately eight to an inch spacer between each blade and on this close up you can see the longitudinal grooving that was left by the diamond grinding operation. Diamond grinding had been completed and the highway opened back up to traffic again. You can see the slight change in color that has shown up here indicating that the slots are there. The surface is smooth but the color is a little bit different. As we zoom in close you can see that the transverse crack has reoccurred through the epoxy, not epoxy, but the concrete grout material that was put in with the rebar. So the transverse crack did reappear immediately. Step in the process was to saw out the existing sealant material in the original transverse joints and longitudinal joints. To do that a blade set up as you see here with two blades with the spacer between them giving a total cut width of approximately one half inch was used on these highly mobile sawing units and in just a few seconds when they get things lined up here will actually see them going along sawing out the sealant material which was still in the original longitudinal and transverse cracks. You can see the residual crack here that they generated was approximately a half inch in width. They can see one of the saws in operation. It moves fairly quickly at this stage of it because they are simply removing the backer rod and sealant material that's in the slot. They're not actually having to re-cut the slot itself because these are existing slots already. So it moves long fairly quickly at this stage. In addition to re-sawing the transverse and longitudinal joints of course there's a step included also of attempting to saw out a reservoir for the sealant material in the transverse cracks at the mid panel transverse crack which has had the dowel bar inserted across it. They use a much smaller blade here because of the irregularity of the crack. It's not just a straight saw cut so it's much more time consuming to try to follow the meandering crack across the mid panel. The blade here is about six to eight inches in diameter again a pair of blades but you can see here the irregular path that is followed and it's going to be much more difficult to seal this particular crack because of the irregular edges of the crack itself. You can see there where they sawed right across the dowel insertion slots and had some pretty crooked crack to try and follow. Makes pretty rough cut but it has cut a slot about a half inch deep. You can see there are places where the crack was missed. Hopefully when they use the air they blew the small pieces out between the saw cut and the crack itself. This is a very difficult part of the process is following this meandering crack in the transverse crack created by nature. Now here you see a location where they realized they'd missed the crack and they had to go back and saw it again leaves kind of an island of concrete they'll have to seal around both sides of that. This location you can see where they saw it along beside the crack but we're not actually right on top of the crack so you end up with a little sliver of concrete between the saw blade cut and the natural crack. This again hopefully will be blown out by the compressed air when they come through to clean these joints out prior to putting the seal into place. Once the cracks have been sawed then we use compressed air and sand again to sandblast the joints of the cracks to clear out the residue left by the sawing operation prior to placing the sealant. This particular machine is set up on a dolly such that they can on the original transverse cracks can just move right along and see it blows it out fairly quickly. Following the meandering cracks was a little more difficult to blow out the material in the meandered cracks. They can see a piece of the sealant material that popped up or the backer rod. Once this machine has blown the bulk of it out there's another man coming along behind this machine with a hand wand to finish the job of cleaning out each crack. You can see him using the hand wand to clean the surface off but also to finish cleaning out any residue that might have been left in the transverse crack. That's a piece of backer rod or an old piece of sealant that was still left stuck to the crack. The next step was to install the backer rod. Some of this slot is approximately half inches wide and inch to inch to half deep so this backing rod which is a foam material is installed in the slot to provide a uniform bottom to the hole and thus when you put the sealant material in you get a uniform cross section. The roller being used here to mash the backer rod down into the crack is simply a large wheel in the center approximately half inch wide, two small wheels on the outside to ride on the surface of the concrete and so here he's just mashing the foam backing rod down into the slot. It has been placed and the final step is to place the sealant in the crack attempting to seal up the joints. It's fairly rapidly moving however you got to try and keep the nozzle in the crack. See occasionally it jumps out but the idea is to put enough sealant in the crack to fill the crack making good contact with both sides of the crack but you do not want it piled up and resin. So the final product as you see here is a seal joint. It's a self leveling type sealant so it does tend to flow down heel toward the edge of the shoulder and create a puddle there at the edge of the shoulder. You can see a little bit of sand laying on top of it but it's recessed below the surface so the tires do not actually make contact with it as they drive down the road. That's the goal. If you put too much seal at the end that it spills out on the surface as you see here and you'll also notice that there's a non sealed where the backer rod did not seal against the sidewalls of either the crack or the joint. You'll end up with a whole pocket in the sealant. Now they did come back and spot check this with a bucket of sealant and try and fill those crevices back up in the spots where there was a noticeable lack of sealant such as right here.