May 9th, 2012

FRENCH CONNECTION

No Comments, Optimize Mobility, by Catherine Higgins.

Engineers from Utah and Idaho recently took a close look at UDOT’s innovative interchanges during the Tour de DDI.

Engineer Gilbert Chlewicki, far right chats with Robert Miles, UDOT Region Two Area Engineer and David Stevens, UDOT Research Project Manager on the Tour de DDI.

A group of engineers gathered for a lessons-learned discussion and tour of UDOT Diverging Diamond Interchanges. Participants met at the Calvin Rampton Complex for review of the UDOT DDIs, then traveled to the SR 201, Pioneer Crossing and SR 92 DDIs stopping briefly at each location.

The event was held to coincide with a visit by Gilbert Chlewicki, a nationally known expert and proponent of the DDI. Chlewicki designed what he believed to be the first DDI in graduate school, then was surprised to find that a similar design was in operation in Versailles, France. Chlewicki spoke briefly about what circumstances make the DDI a better choice than a traditional Single Point Urban Interchange and about how to promote public knowledge and acceptance.

Though it’s “not a silver bullet” that will solve any traffic problem, Chlewicki believes the design is best used in an urban or suburban environment. In fact, Chlewicki predicts that the design should be considered first in an urban or suburban environment and will “make the SPUI extinct.”

Public perception of the DDI can be positive when communication stresses two messages, according to Chlewicki. Communicators need to explain how the DDI can reduce delay and make life better for road users and focus on how the design can actually improve safety. “As long as you explain it well” public acceptance is high.

Other presenters included:

  • Richard Miller, with Parsons Transportation Group lead designer of the Pioneer Crossing DDI
  • HG Kunzler with Lochner Engineering who designed the retrofit DDI at SR 201 and Bangerter Highway
  • Michael Lasko with CH2M Hill who designed the SR 92 DDI
  • Glenn Blackwelder, UDOT who discussed operations in Region Three
  • Marjorie Rasmussen, UDOT who discussed operations in Region Two

Designers gave an overview of the DDI design process and discussed lessons learned along the way, reviewed issues associated with “retrofit” DDIs, discussed “wrong way fear” and mitigations to help the driving public.  Glenn Blackwelder and Marjorie Rasmussen discussed current operations.

Blackwelder said the DDI is “the sportscar of interchanges,” because it’s fast, flexible and well-tuned. As a traffic engineer, he finds DDIs “fun to operate.” Although initial coordination can be tough and time consuming, operational changes make improvements and improve traffic flow.

Engineers from Idaho attended the event to prepare to design and construct a DDI in Chubbuck, Idaho. “We took some valuable information from the events of the day,” wrote Jesse Barrus in an email thank-you to UDOT following the event. “Being the engineer of record on this project I really appreciate the confidence I got from the operational standpoint of these innovative designs.”

May 8th, 2012

MAP IT

No Comments, Optimize Mobility, Strengthen the Economy, by Catherine Higgins.

By Catherine Higgins and Daniel Kuhn

A small map is a big deal for commercial truckers who drive through Utah.

The New UDOT Truck Parking Map is a schematic showing the location of commercial truck stops and UDOT rest areas along I-15 as well as the other Interstate Highways in Utah. UDOT is not aware of any other state producing a similar map.

The schematic shows the number and location of parking spaces in Utah for commercial truckers. That information is important for two reasons:

First, Utah is strategically significant to North America’s commercial trucking industry, and it is easy to see why by just looking at a highway map of the United States. I-80 is the backbone of routes crossing the middle section of the nation, on which freight moves to, from, and through Utah en route to points all across the USA and Canada. Northern Utah is the junction of two of I-80’s most important feeder routes – I-84 from the Pacific Northwest, and I-15 from Las Vegas and southern California.

The UDOT Truck Parking schematic shows the location of truck stop and rest stop parking.

A large percentage of the trucks traveling through Utah, particularly in the summer and fall, are refrigerated “reefer” trucks carrying perishable, time and temperature-sensitive foodstuffs. A large portion of what America eats passes through Utah in reefer trucks every day. On I-80 east of the junction with I-84 in Echo, Utah, reefer trucks amount to more than 50% of total truck traffic, which averages about 5000 truck per day during the western growing season.

Because of Utah’s crossroads status, UDOT’s highways handle a disproportionately high amount of freight for the entire country as well as Canada. This result in a correspondingly high number of distribution warehouses being located in the Beehive State. Several refrigerated truck companies are headquartered along the Wasatch Front, including the world’s largest, C.R. England, Inc.

Utah’s crossroads status for highway freight is further reinforced by our having the highest percentage of truck traffic of all 50 United States. According to the latest federal highway data, 23% of total traffic on Utah highways is trucks, compared to a national average of only 12%. While Utah roads are used to move a myriad of products from all over the continent, only 10 to 12% of the freight moving on Utah highways is actually consumed here in Utah.

The second factor that makes the new Utah Truck Parking Map a useful tool has to do with federal rules that govern rest breaks for truck drivers. Hours of Service laws are meant to keep our highway system safe by preventing crashes caused by driver fatigue. Drivers of commercial motor vehicles such as trucks and buses are required to take mandatory rest and sleep breaks. However, there is currently a shortage of long-term parking for trucks across much of the nation, making it difficult for drivers to find places to park to get their required rest.

The UDOT Truck Parking Map provides truck drivers a compact source of information about the location of long-term truck parking, as well as what amenities are found at each truck stop or rest area. This allows drivers to better plan their rest stops and reduces the number of drivers who “park on off ramps or on the side of major freight highways,” explains Vern Keeslar, Senior Planner with InterPlan. Daniel Kuhn, UDOT’s Railroad & Freight Planner, and Keeslar worked together to develop this useful tool for commercial truckers.

Funded by a federal grant, this effort included interviews with more than 400 truck drivers, as well as the managers of commercial truck stops along the I-15 corridor.When truckers were asked what tool would be most helpful, a durable map or parking locations was number one on their list. The Utah Truck Parking Map was the result, which is printed on waterproof, tear-resistant paper, and allows drivers to avoid using electronic communication technology while driving which can create distractions, safety hazards, and is forbidden by law in many states.

The Utah Truck Parking Map is being placed at commercial truck stops, UDOT Ports of Entry, selected distribution warehouses, and 2000 copies will be distributed by the Utah Trucking Association through their in-house magazine.

Keeping freight moving safely and efficiently on Utah highways is a key element in supporting and maintaining robust economic activity here in Utah, at the Crossroads of the West.

May 4th, 2012

REST AREA CONFERENCE

No Comments, Uncategorized, by Catherine Higgins.

UDOT is hosting the National Safety Rest Area Conference being held September 17 through 20 2012 in Salt Lake City, Utah.

One of UDOT’s newest SRAs is a tribute to Utah’s railroad past. Tie Fork is modeled after a railroad round house and interpretive panels have snippets of area history.

The conference provides a venue for planners, vendors, public welcome center managers and maintenance providers from across the United States and Canada. Attendees meet and share best practices for planning, constructing and maintaining the buildings and picnic and tourism information spots that serve people who travel along the Interstate Highway system.

The NSRA is part of AASHTO’s Maintenance Sub Committee, and responsibility for organizing the conference is accomplished by state transportation agencies. This year, UDOT takes the lead with support from the Kentucky Department of Transportation. Besides breakout sessions focusing on aspects of planning and maintenance, the conference will also include a day-long tour of some of the rest areas in Utah.

The primary purpose Safety Rest Areas is to provide a place to take a break while traveling long distances. Since the Interstate system offered limited access, SRAs are a way to replace roadway parks and stores as a stopping point for travelers.

The first SRAs were built along with the Interstate Highway System in the 1950s and 60s, according to Rest Area History.org. “SRA structures and the sites on whole were to be both functionally and aesthetically satisfying, creating environments that were at once relaxing and engaging” by offering travelers a view of the local culture through architecture or even art installations. More than just a place to stop, eat and rest, “…these sites illustrate an important aspect of the American travel experience and specifically articulate our experience of travel as it was shaped by the Interstate era beginning in the 1950s.”

Like most SRAs across the country, UDOT SRAs provide the basics – toilet facilities and drinking water, and many have picnic areas and a place for travelers to pick up information about or maps of the areas. One of UDOT’s newest SRAs is a tribute to Utah’s railroad past. Tie Fork is modeled after a railroad round house and interpretive panels have snippets of area history.

May 3rd, 2012

STOPPING SCOUR

No Comments, Preserve Infrastructure, by Catherine Higgins.

UDOT has recently surveyed bridges over waterways with unknown foundations and identified which is at risk for scour.

Montezuma Creek

Over time, water can excavate soil and rocks from around bridge piers, piles and abutments causing bridge scour and putting the structure at risk for premature failure. Scour can happen gradually on structures with constant slow moving water or quickly during a flood event.

This concrete wall provides a permanent fix for scour.

Bridge inspectors check for scour along with other structural features of bridges on regular inspections that occur within every 24 months. For bridges over waterways, inspectors look at the bridge structure, orientation, geomorphic conditions , the type of rock or soil near the abutments, the location of sediment carried by the water, and the angle, magnitude and duration of the flow. Inspectors also check piers or piles for evidence of scour holes (where water has excavated soil from around structures) or corrosion on structural elements.

Inspectors take detailed notes about the location of potential or actual problem areas. Close regular monitoring is a way to “keep our finger on the pulse of the bridge,” explains UDOT Central Hydraulics Engineer Denis Stuhff.

After inspection, a Plan of Action is developed for each bridge that includes management strategies and countermeasures for keeping the bridge safe for the traveling public before, during and after a flooding event. Sometimes permanent structural countermeasures are taken; however the most common countermeasure is the addition of strategically placed riprap.

Placing riprap is an economically sound and effective approach that allows UDOT to address the potential of scour at all bridges rather than just a few since pinpointing which bridges will be vulnerable from year to year is not an exact science. “At any time, any bridge over a waterway may have a flood,” says Stuhff who uses a gambling metaphor to explain.

“Catchment areas in Utah are like one big casino. We put our hydrology quarter in our hydrology slot machine once a year and we pull the handle… somewhere in the state, it’s paying off.”

John Njord received the Distinguished Alumni Award from the University of Utah Department of Civil Engineering.

UDOT Director John Njord

Njord received the Distinguished Alumni Award and was inducted into the CE Academy. The award is given to an “alumnus that has been influential in education, industry, business, government, or construction,” according a Department of Civil Engineering newsletter.

Njord’s leadership has “made this transportation agency the envy of transportation agencies across the country and in fact, around the world,” says UDOT Deputy Director Carlos Braceras. “John is one of those exceptional leaders that allowed every employee in this agency to be their best.”

Njord joined the Utah Department of Transportation in 1988 after graduating with a Bachelor of Science in Civil Engineering degree from the University of Utah. He worked as a Field Engineer, Local Governments Liaison Engineer, Engineer for Urban Planning, Director of Olympic Transportation Planning and Deputy Director before becoming Executive Director in 2001.

Braceras credits Njord’s “natural leadership and his caring for the employees” for making UDOT “a productive place to make a difference.”

Njord said he was “shocked” and “obviously honored” on learning of his selection, especially in light of previous recipients and their accomplishments in this community. “I realize that in many ways I am the face of the department – I am the front guy,” he said. Njord believes that the  accomplishments made by department employees “has drawn recognition to me.”

Under his direction, Njord has led the effort to use innovative solutions to improve the transportation system in Utah. UDOT leads the nation in Accelerated Bridge Construction. Thirty-seven bridges associated with interstate highways have been built off-site and moved into place. The agency has pioneered the design and construction of innovative intersections and interchanges that have enhanced traffic mobility.

His role as he sees it is “to provide an environment where folks feel like they can solve problems.” Njord seeks to foster “a healthy environment where the best ideas can come forward.”

While some think of engineers as professionals who seek to work strictly by the book, Njord takes exception to that view. “True engineering begins as textbook engineering,” said Njord. “When you depart from ‘chug and plug’ engineering, all the innovation lights can turn on.”

Njord believes that any engineering problem can be solved when employees are willing to explore any idea. “And in the end, we are doing a great service for the citizens of our state.”

“I believe most of our employees go home and think ‘we’re doing good things.’”

The other CE Academy inductees are:

C. Ross Anderson
David Eckhoff
Paul Hirst
Jim Nordquist
Ron Reaveley

April 30th, 2012

DDI DESIGNER

No Comments, Optimize Mobility, by Catherine Higgins.

National DDI expert and advocate Gilbert Chlewicki will give the keynote address at the UDOT Research Workshop on May 10.

Gilbert Chlewicki

Chlewicki developed the design for the Diverging Diamond Interchange as a graduate student. After designing the innovative interchange, he visited France and on a bus tour, was surprised to see that the design was already in existence.  While disappointed that he was not the first, he continued to work on the DDI. Chlewicki has pioneered other designs as well, including the Continuous T Intersection, which he will discuss in detail at the workshop.

As a forward to his keynote address at the workshop, he answered some questions about non-traditional transportation designs.

What prompted you to want to develop non-traditional designs?

“I’ve been designing roads since I was a little kid.  I used to draw long stretches of highway on old dot-matrix computer paper that had each sheet of paper attached to the next.  I used to make the lanes wide enough for my hot wheels to drive on my roads.  The drawings had full signing and traffic controls.  When I would finish a drawing, I would stretch it out across the house and have my younger sisters drive on them to find certain destinations.  In high school, I made my lanes narrower so that I could fit more into a drawing and eventually created a new highway (which I called I-74) that went from New Jersey, through southern Pennsylvania, Ohio and finally to Indiana.

My drawings were always in pen, so when I would make a “mistake”, I would incorporate the mistake into the final design.  Anytime I drew a more complex design, I would always try to figure out how both the geometrics and traffic operations would work and then think about what I could do to improve the design for the future.  I came up with several designs on my own before I even knew they existed such as a roundabout and a single point urban interchange (SPUI).  There were other designs that I still believe are original concepts.  So I’ve been developing unique geometric designs for nearly 30 years now and am still continuing to come up with new designs.”

Are transportation agencies/engineers initially resistant to the DDI or other non-traditional designs? Why, and what has to happen for that resistance to be dropped?

“There has been a lot of resistance to non-traditional designs.  Just as an example, the modern roundabout has been around

An aerial photo of I-44 / Kansas Expressway Diverging Diamond Interchange in Springfield, Missouri. First of its kind in the U.S. Photo from Missouri Department of Transportation.

nearly 50 years but it has only gained partial acceptance in the US over the past 10-15 years even though it is a great design.  There are over 40 unique documented non-traditional designs but about half of these designs have never been constructed even though they show promise.  Of the 20+ designs that have been constructed, many of those you can only find sporadically in the country (ex. one echelon in Florida) or prominently in one state (ex. the jughandle in New Jersey, the median u-turn in Michigan).

The DDI has been very fortunate to gain acceptance very quickly across a lot of the transportation world and my hope is that the DDI will be the main example that helps stimulate building other non-traditional designs.  However, there is still resistance to the DDI in a large part of the transportation world.”

“There are many different reasons for the resistance of non-traditional designs.  Some are due to not wanting to change when a more well-established design could work almost as well.  Some are due to consultants not thinking that their clients will accept something different and “unproven”.  Some don’t want to try something new.  Some are worried about liability.  Some are scared to fail.  Some think that these designs cost too much.  Some don’t even know that these designs exist and most of those that know they exist don’t understand which design is best.  And some are scared of the politics and/or community acceptance.

I think three big things need to happen for this resistance to change.  One, we need to educate every one of these designs.  There’s enough information out there now and the more people know and understand, the more willing they will be to try these designs.  Two, we need champions of non-traditional designs in both the consulting world and in transportation agencies.  When we have the right people promoting these designs, the resistance will begin to fall.  And three, we need to create a more innovative culture in the transportation industry.  When we promote innovation, we will be more likely to accept it.”

How has the driving public accepted DDIs?

“For the most part, the public has been very accepting of DDIs, perhaps even more accepting than the transportation industry.  When the public sees how easy it is to navigate in the DDI and then they see the benefits of the design in terms of the traffic operations, costs, and safety improvements, it becomes a no-brainer to most of the public.

I worked on a planning project back in 2005, where we had a DDI as one of our options.  This might have been the first project that was considering a DDI in the country.  All of the alternatives had the interchange operating at a LOS A or B in the design year, so there was little benefit from an operations point of view of the DDI versus any other alternative.  The public still voted for the DDI over the other alternatives.  Ultimately the DDI was not selected because the agency did not think it was the proper location to put the first DDI in the state and since it was a new interchange, the DDI did not show any inherent benefit over the other alternatives in terms of traffic operations or costs.”

In your opinion, what is the future of the DDI in the US?

“The future is extremely bright for the DDI in the US.  I wrote a paper that was published in Transportation Research Record last year that showed that the DDI will likely be the best option for a multi-lane arterial of any diamond form regardless of turning movements, when considering costs and traffic operations.  I think the DDI will replace the need to build any more SPUIs, except in a few situations where it might be better geometrically.

In my opinion, the DDI should be considered as an alternative for all interchange projects because of the many benefits of the design.  It may not be the best solution in every case, but it has enough benefits to merit consideration.  We have a similar policy in Maryland concerning roundabouts.  All projects in Maryland must consider a roundabout for any intersection improvement.

I can easily see there being over a hundred DDIs across the country by the end of the decade.  And when you consider that the DDI on average costs roughly $10 Million less than the next best alternative, the country should be saving over $1 Billion in transportation costs!”

Your new Continuous T sounds interesting! Can you send an explanation and maybe refer me to some information online?

“The Two-Way Continuous-T Intersection allows non-stop flow of thru traffic in both directions of a T-Intersection without any grade-separation, while at the same time vastly increasing the percentage of green time for the left turn movements.  How is this possible?  The design takes concepts from three other innovative intersections (the Continuous-T Intersection, Continuous Flow Intersection, and Double-Wide Intersection) to create this new design.  You can get more information on this design from the materials in the 2012 TRB annual meeting where you can find my paper and poster that I presented.  If time permits, I will be talking about this design during the keynote address as an example of how innovation is developed.”

April 27th, 2012

CHANGING LIVES

No Comments, Uncategorized, by Catherine Higgins.

Public transit is more about people than buses.

Todd Beutler, Cache Valley Transit District General Manager had a “changing moment” that prompted him to consider a career in public transit. As a student, he worked as a bus driver and became acquainted with an elderly man who rode the bus every day. One day, Beutler had a conversation with the man and became acutely aware of how important bus service was to his independence and quality of life.

Eight agencies in Utah provide public transit and para-transit public transportation in service areas across the state. However, some parts of the state are not covered by those service areas. The Federal Transit Administration, part of the US Department of Transportation, sponsors 21 grant programs, 6 of which are specific to special rural areas and low income, elderly and disabled citizens. In Utah, those programs are administered by the UDOT Public Transit Team staff that assist qualifying local communities to apply for and obtain funding to meet operational and capital needs.

According to the PTT Annual Report, the program allocated more than $4,733,886 in FTA grant funds to public and private agencies and organizations across the state. Many of the funds help support existing services by purchasing additional buses or equipment, such as GPS systems, that help communities expand public transit routes. The funding helps support “improved access and quality of service in urban and rural areas statewide.”

Thousands of citizens in Utah have benefited from improved public transit services. A new video details how the work of the UDOT PTT is really about people. In addition, local economies have benefited when people can connect to services, education and employment.

April 26th, 2012

NEW CROSSWALK

No Comments, Uncategorized, by Catherine Higgins.

A new cross walk with multiple signal phases is now in operation in North Salt Lake.

A new cross walk is in operation on Highway 89 at 800 West in North Salt Lake, Utah. A Federal Highways Administration study of the HAWK showed “yielding percentages above 95 percent."

The new crossing, a High intensity Activated crossWalk – called a HAWK – was designed in Tucson, Arizona appropriate for use at high volume or wide arterial streets with minor street intersections. HAWKs gives drivers “multiple cues to emphasize the potential presence of a pedestrian,” according to a Federal Highways Administration study that tested the effectiveness and safety of the HAWK. The study found that the yield rate is high due to those multiple visual cues.

The HAWK crossings include prominent pavement markings, signage and red and yellow lights on an over-the-roadway arm. When not is use, the lights are dark. Just like regular crosswalks, HAWKs are triggered when a pedestrian pushes a button. First, double yellow flashing lights, then solid yellow lights are activated to warn drivers to stop. The yellow phase is followed by two solid red lights to signal traffic to stop.

Pedestrians are then given the walk symbol followed by a countdown showing how many seconds remain in the walk phase. During the count-down, a flashing red light warns oncoming motorists to come to a full stop – motorists can proceed after a full stop if pedestrians are out of the crosswalk.

The FHWA study of the HAWK showed that “yielding percentages above 95 percent for the HAWK treatment, even on major streets with multiple lanes or higher speeds.”

Although the study also mentions that drivers are most likely to fail to yield during the flashing red phase. “Some drivers don’t seem to know what to do,” during the flashing red phase says Larry Montoya, a Traffic and Safety engineer at UDOT. Drivers encountering a flashing red signal on any roadway location should first come to a full stop, make sure the way is clear, and then proceed.

At a HAWK, drivers should come to a full stop and make sure pedestrians have cleared the crosswalk before continuing on. The flashing red phase is a way to balance the needs of pedestrians while limiting traffic delay.

April 25th, 2012

ZONE DEFENSE

2 Comments, Uncategorized, by Catherine Higgins.

Three out of four work zone crashes are caused by drivers.

UDOT limits construction delay as much as possible but some delay is inevitable. Use UDOT Traffic to check your route and leave early or take an alternate route.

It’s road construction time, and UDOT has over 200 active work zones.  The most important thing drivers should remember is to “slow down and pay extra attention when driving through a work zone, especially this year when we have so many projects,” said UDOT spokesman Nate McDonald in an article in the Standard Examiner.

An Associated General Contractors of America survey found that 68 percent of contractors said that motor vehicles crashed into their construction work zones during the past year. The same study also found that work zone crashes are more likely to kill construction workers than vehicle operators.

“Any time your job site is just a few feet away from fast moving traffic, things can get a little too exciting,” said Tom Brown, chairman of AGC’s national highway and transportation division. “Since construction workers don’t get the option of wearing seatbelts, they are more likely to be killed in a work zone crash than motorists are,” he stressed.

When driving in work zones, remember to manage your speed, your space and your stress. Here are some great tips:

  1. Slow Down when approaching all work zones. You will be in the work zone quicker than you think.
  2. Follow Posted Speed Limits, especially within construction zones, and try to maintain a consistent speed with the traffic flow. And adjust your speed for weather conditions.
  3. Don’t Resume Normal Speed until you see roadway signs indicating it’s safe to do so.
  4. Leave braking room, at least two car lengths, between your vehicle and the one ahead of you. The most common crash in a highway work zone is a rear-end collision.
  5. Keep a safe distance between your vehicle and traffic barriers, trucks, construction equipment and workers.
  6. Don’t pass on the shoulder or drive across the median – doing so creates a very dangerous situation for you, workers and other motorists.
  7. Watch out for tailgaters and don’t force tailgaters to back off by slamming on your brakes or reducing your speed significantly.
  8. Stay calm and don’t rush. Construction zone inconvenience means that improved roads are soon to come.
  9. Pay attention and avoid distractions like cell phones or the radio.
  10. UDOT limits construction delay as much as possible but some delay is inevitable. Use UDOT Traffic to check your route and leave early or take an alternate route.

April 24th, 2012

DOCTOR SEEKS SLOW CURE

No Comments, Preserve Infrastructure, by Catherine Higgins.

Prolonged internal curing promises to help concrete resist shrinkage and cracking.

Concrete designed for internal curing resists shrinkage and cracking. The small plywood square in the foreground is a temporary cover for a sensor embedded in the concrete that will help researchers gather data.

BYU researcher Dr. Spencer Guthrie is comparing and evaluating the performance of concrete on two concrete bridge decks – one is made of regular concrete and the other is made with “pre-saturated lightweight aggregate fines,” explains Guthrie.  “My particular task is to quantify the differences between this type of concrete and conventional concrete in bridge deck applications.”

Adding the wet, fine aggregate causes prolonged internal curing which has been shown to reduce shrinkage and cracking in concrete.* Internal curing also makes the concrete less porous and therefore delays the intrusion of water and dissolved chemicals and minerals that eventually cause the steel reinforcement to corrode.

A detailed explanation of internal curing can be found in a YouTube video of a presentation given by Dr. Jason Weiss of Purdue University School of Civil Engineering. According to Weiss, “internal curing increases hydration and ‘densifies’ the system.”

Concrete (basically cement and aggregate) cures through a chemical reaction, called hydration, which occurs when water saturates the cement. Internal curing is especially useful when it comes to high performance concrete that has a very dense aggregate matrix. Concrete mixes that are designed to be dense and structurally robust restrict water movement during the curing process.

Pre-wetted aggregate temporarily holds water in the concrete mixture without increasing the water-cement ratio.  As the hydration unfolds, tiny pockets of water in the aggregate continue to react with the cement. “When we get more internal curing water, we keep the system moist, we keep the system reacting, we keep hydrating the cement which means we’re going to have lower overall porosity in the system,” says Weiss.

Guthrie and engineers at UDOT will eventually have objective data that will show the differences between conventional concrete and concrete designed for internal curing. Sensors embedded in the concrete measure time, water content, temperature, and electrical conductivity, which is a good representation of permeability. Guthrie and others will also conduct strength and durability tests in the lab.

Weiss claims that internal curing can effectively double the life of bridge decks, making it possible to use transportation resources more wisely.

 *According to Guthrie: “Shrinkage always happens before cracking (and is often the cause of the cracking).”