Bridge Preservation Training for Local Agencies

By Lorella Angelini, Angelini Consulting Services, LLC

The Local Agency Outreach TSP2 Working Group has developed a new program, the Bridge Preservation Training for local Agencies, whose main points are reported in the “Low-Cost Maintenance to Save Bridges” flier. The flier, which is published on the TSP2 web site, can be found on the Local Agency Outreach Working Group page, following the link: “Local Agency Outreach Introduction White Paper.

The new program is in line with one of the strategic goals of TSP2 that entails extending the use of bridge preservation practices from DOTs to local Agencies, such as Cities, Counties and Municipalities. In order to learn more about the program, I spoke with Gregg Freeman, Director of Business Development with Kwik Bond Polymers and chair of the Working Group, and with Travis Kinney, Major Bridge Maintenance Engineer with Oregon DOT, co-chair of the Working Group, and project leader. I also contacted Pat Conner with Indiana LTAP for information concerning this State.

How was this new program formulated?

Travis Kinney, Major Bridge Maintenance Engineer with Oregon DOT

Travis Kinney – The TSP2 Partnership recognized that the local Agencies did not have enough presence and influence in the Bridge Preservation Partnership group. I do not mean to say that there are not active members from local Agencies in TSP2, but their number and their level of influence is not proportional to the amount of bridge inventory they manage. As a consequence, a TSP2 Working Group was developed to look at ways to improve the outreach to local bridge owners with the goal to educate them about the benefits of preservation practices. Setting up a bridge maintenance training for local Agencies was an idea that spawned naturally out of this effort.

The Local Agency Outreach Working Group has progressed to include great participation from a wide range of local Agencies. This participation has helped the group in many respects including the design of ways to advertise training opportunities. These encompass advertising the activity of the Working Group in the National Local Technical Assistance Program Association (NLTAPA) (see LINKS) newsletters, the creation of a flier, and even a poster-board to be displayed at the national LTAP conference, which unfortunately was canceled because of COVID-19.

What is the purpose of the program?

Gregg Freeman, Director of Business Development with Kwik Bond Polymers

Gregg Freeman – We aim to educate local Agency managers on the benefits of preservation versus replacement of bridges. Preservation is a proven methodology that saves taxpayers’ money over the long term.  At this point, there isn’t nearly enough money available to replace bridges that are in “poor” condition.  Preservation is the only methodology to be considered in order to close the gap.

What are the key elements of the program?

Gregg Freeman – A strict collaboration with LTAP people is essential in order to implement our process of soliciting local Agencies to adopt bridge preservation practices. We thought that a simple and effective way to initiate this collaboration was to create a non-proprietary presentation, titled “Bridge Preservation For Local Agencies”.

This presentation, which was the first output of our TSP2 Working Group, is intended to be given as part of the “Lunch & Learn” LTAP training program throughout the US. The intent of the presentation is to underscore the importance of a pro-active bridge preservation approach, summarized in the “Keep Good Bridges Good” mantra, as opposed to a reactive “Worst First” methodology that should not be the focal point of any asset management plan.

Travis Kinney – The Working Group is now focused on identifying barriers that prevent obtaining funds for preservation at local levels. As a result of this effort, the group identified that federal funds are rarely used at local levels for preservation activities. Replacement and major rehabilitation tend to be favored in existing projects’ selection processes. In addition, state funding tends to favor the “Worst-First” approach.

Another key initiative of the Working Group that has just started entails the review of asset management plans by local Agencies in order to determine whether they create a framework that favors replacement instead of preservation practices.

Who is the target audience of the “Bridge Preservation For Local Agencies” presentation?

Gregg Freeman – It is a large target audience. It includes Cities, Counties, Municipalities, Tribal Agencies and every group involved with educating local Agencies, such as LTAP, NACE, FHWA, State DOT’s and AASHTO.

Has this presentation already been given?

Travis Kinney – The presentation is ready to be given and is being advertised through the NLTAPA Working Group members.  In April of this year, I gave a trial run of the presentation virtually to over 30 LTAP representatives. The presentation was well received and the Working Group has gained interest in setting up virtual training opportunities.

Can you tell me more about the issue concerning access to federal funds?

Travis Kinney – As I mentioned earlier, how to get access to federal funds for preservation is a point of key interest for local Agencies.

We had reached out to our contacts at TSP2 for good examples of funding for local Agencies, specifically for preservation. When they told us that they had a hard time finding these examples, we started working with the Bridge Preservation Expert Task Group (BPETG) from FHWA (see LINKS) so as to establish a study, or a survey, that can be valid on the national scale. This is being framed out.  The key question that we would like to have answered through the collaboration with BPETG entails barriers for getting funds down from federal to local level for preservation.  The best funding example we have found so far entails the state of Indiana, which has done a great job of promoting preservation at the local level.

Pat Conner, LTAP Research Manager with Purdue University

Pat Conner – The Indiana transportation funding system encourages preservation through different avenues, such as the use of revenue from the gas tax that is distributed to locals, a new state funded matching grant fund, and obviously locally generated funds. The Indiana model is however difficult to duplicate in other states because most of the funds used for preservation are funded locally or from state generated funding. In Indiana federal funding is not currently being utilized for preservation.

Indiana has the Motor Vehicle Highway Account, which is heavily funded through gas and diesel taxes. Local Agencies are required to spend at least 50% of this account toward construction, reconstruction, and preservation. Indiana also has a matching grant fund for local Agencies that is funded through vehicle registrations and a portion of the gas tax. In order to get access to this fund, local Agencies are required to have an asset management plan in place. Between the funding availability for preservation, the asset management requirements, and the training being provided for asset management by LTAP, Indiana is the forefront of creating a culture that encourages local Agencies to re-look at their project priorities and preferred practices.

Gregg Freeman – In some cases, bridge preservation is still being confused with major rehabilitation and replacement. One of the first examples of federal funding for local Agencies we received from FHWA was under the banner of bridge preservation but it actually involved major rehabilitation and replacement. It did not entail preservation, as it is defined by AASHTO TSP2 as “actions or strategies that prevent, delay or reduce deterioration of bridges or bridge elements, restore the function of existing bridges, keep bridges in good condition and extend their life”.

Could you share details about the current state of the program’s implementation?

Gregg Freeman –  Travis gave a webinar organized by the National LTAP that was attended by 30 people. I had the opportunity to give a preliminary version of the “Bridge Preservation For Local Agencies” presentation at the annual county bridge conference organized by Indiana LTAP at Purdue University on October 29 and 30, 2019. I was invited by Pat Conner, who has been instrumental in creating such a good training program for local Agencies in Indiana.

Travis Kinney – We have had tremendous support for doing more in-person presentations. North Dakota, Wisconsin, Nebraska and Illinois had all reached out to our Working Group because of their interest in the program. This was in early March. Since then in-person training has been put on hold due to the COVID restrictions. We are now shifting gears and looking at virtual training opportunities to sustain the Working Group’s momentum.

The training comes at no cost for those attending. Who pays for it?

Gregg Freeman – When in-person meetings can be organized again, we are counting on the collaboration of volunteers from the local LTAPs, local FHWA, State DOTs and industry.

Primarily we are looking for industry folks who volunteer as presenters, preferably with a partner from a State DOT. We already have a list of potential industry presenters. We are relying on LTAP to help set up the meetings and provide a venue. Alternatively, the venue can be provided by State DOTs that participate in the program. The FHWA BPETG is also supporting this effort.

Travis Kinney – With virtual meetings the organization process could be simplified. However, at this point, organizing virtual meetings on a national scale is a work-in-progress with a number of pieces to be defined.

 

LINKS

Local Agency Outreach Working Group

National Local Technical Assistance Program Association (NLTAPA)

Bridge Preservation Expert Task Group (BPETG)

 

A Conversation with John Hooks, TSP2 Bridge Preservation

John Hooks with TSP2 Bridge Preservation

By Lorella Angelini, Angelini Consulting Services, LLC

John Hooks is a key part of the TSP2 Bridge Preservation team. He combines depth of engineering knowledge and technical competence about bridges with great people skills, the ability to listen and to build strong personal relationships.  I had a chance to ask John a few questions at the recent TSP2 Midwest Bridge Preservation Partnership (MWBPP) meeting that took place in Bismarck, ND.

Could you outline the pivotal points of your career as bridge engineer and speak of your professional experience with FHWA?

 I joined the Federal Highway Administration (FHWA) in 1967 after receiving a BSCE and an MSCE in Structural Engineering at Clarkson University in Potsdam, NY. After rotating through several short assignments on a training program, I served as the Assistant Division Bridge Engineer in FHWA’s New York Division office. In 1975 I transferred to the FHWA Office of Research & Development in the Washington, DC area. This transfer helped define the remainder of my career with FHWA as a specialist in bridge engineering. I spent 23 years developing programs to implement the results of research done by FHWA as well as certain research done by state DOTs and the Strategic Highway Research Program (SHRP).

The main focal points of my work were bridge inspection, bridge management and bridge preservation. Two of the most notable results were: the 1990 Bridge Inspector’s Training Manual and the associated training courses; and the original DOS version of the bridge management system, Pontis – the basis of the current AASHTO BrM.

The final several years of my FHWA career, I served in the Research section of FHWA Office of R&D where I was the Director of Structures Research. I retired from FHWA at the end of 2004.

How did you get in contact with the TSP2 team? When did you join TSP2 Bridge Preservation?

In 2006, I joined an engineering firm, ENCINC in Virginia. One of my early projects with ENCINC was an FHWA study to develop a Transportation System Preservation (TSP) Research, Development, and Implementation Roadmap which FHWA published in 2008. The TSP2 team at the National Center for Pavement Preservation was a subcontractor to ENCINC for this project and I came to know the TSP2 team well.

Two other projects followed where I served as a consultant to NCPP. I first learned about the TSP2 Bridge Preservation program when I gave a presentation at the 2010 WBPP meeting. In 2012, I became a regular member of the NCPP TSP2 team and have been involved with the Bridge Preservation program and all its activities since then.

What are your main responsibilities at TSP2?

At TSP2, I have multiple responsibilities. The main one is working closely with all four of the Regional Partnerships and assisting with the development, organization and conduct of the annual regional meetings and the national meetings that take place every four years.

Each meeting attracts from 180 to 200 attendees, including industry representatives from 45 to 50 companies who exhibit.

I participate in all of the regular monthly calls and work closely with the eight TSP2 national Working Groups, such as the Bridge Management Systems Working Group for which I am recording secretary.

As a staff member at NCPP, I also work on research projects that the Center undertakes under contract with clients such as FHWA, NCHRP and Michigan DOT.

What do you enjoy of these responsibilities? On the other hand, what do you find most challenging?

Many aspects of my responsibilities are enjoyable. Meeting and collaborating with bridge preservation experts across the nation is satisfying as well as highly educational. There are always new things to learn about bridges and bridge preservation.

Working closely with the many attendees and with the members of the national Working Groups is rewarding, especially in that these volunteer groups develop products that have a significant impact on the practice of bridge preservation.

Of course, travel to the various meeting sites is almost always a pleasure. Partly because of my position at NCPP I have been in all 50 states, Puerto Rico, the District of Columbia and several foreign nations.

Two of the most challenging aspects of the position are the breadth of preservation technology that I need to be aware of and understand plus the difficulty in measuring the impact of the TSP2 activities on the bridge infrastructure. In many cases, the scope of the impact cannot be determined until many years have passed.

How does your bridge preservation experience at TSP2 differs from FHWA?

The main difference is that with FHWA my efforts were in pursuit of new technology for inspection, management and preservation of bridges. With TSP2, the main thrust of my efforts is to connect with a wide audience of bridge preservation practitioners and assist them in identifying, assessing and ultimately adopting new practices that improve their ability to preserve bridges.

What is your vision for TSP2 Bridge Preservation? What works? What would you like to improve?

The TSP2 program maintains contact with a wide audience of bridge preservation practitioners in state DOTs, local agencies, FHWA, academia and the private sector. The TSP2 staff has several avenues for maintaining a dialogue with those people: through management of the annual regional meetings and the quadrennial national meeting; through participation with the national bridge preservation Working Groups, the FHWA BPETG, and relevant TRB committees; and by providing technical services to the partnerships and individual agencies. This constant communication is the backbone of a collaboration that works quite well. Additionally, over the years, NCPP has amassed an unparalleled library of technical information on a broad range of bridge preservation topics.

What I would like to see happen is that to a greater degree than now, the TSP2 program be recognized as the first stop for bridge preservation information. The other thing I would like to see is a strengthening of current efforts to involve and deliver that information to local bridge owning agencies.

Would you like to share something about your personal life? Are you a morning or an evening person? What do you do like to do in your free time? What is your favorite book?

Sure thing. I am married, and my wife Linda and I have six children and a dozen grandchildren. In addition to enjoying all of them, Linda and I love to travel overseas and experience different cultures, languages and environments.

Most of my life I have been a morning person and for my entire adult life I have been a “fitness buff” and a runner for over 55 years. I do play a little golf (poorly) but my main passion for my free time is reading, mysteries and historical non-fiction being my favorite genres. My favorite book of all time is John Barry’s masterpiece “Rising Tide: The Great Mississippi Flood of 1927”, a fantastic book about Mother Nature, human nature and the engineering of civil works.

Reports from the MWBPP Working Groups

Author: Lorella Angelini, Angelini Consulting Services, LLC

At the recent TSP2 Midwest Bridge Preservation Partnership (MWBPP) meeting that took place in Minneapolis, the Working Groups met to discuss the status of their activity and outline future developments.  I asked the leaders of the Working Group meetings in Minneapolis if they could write a summary for the Blog.

Preservation Matrix: Dave Juntunen, Michigan DOT

Dave Juntunen with Michigan DOT

The working group concurred that the preservation matrix is still desired and the working group should be continued. New members volunteer.

The current deliverable of the working group is an Excel spreadsheet showing what preservation activities the partner states do by contract and state maintenance forces. Unfortunately few people ever see the matrix or even know of its existence. The group would like to update the matrix and make it available to the bridge preservation community by placing it on the on the TSP2 MWBPP website. The matrix should be updated to include links to training and state specifications. Analysis of the matrix can be done to show trends in preservation and a blog written to introduce the website and provide outreach to partner states and local agencies.

Systematic Preventive Maintenance (SPM): Scott Stotlemeyer (chair), Missouri DOT

Scott Stotlemeyer with Missouri DOT

25 attendees met to discuss the current and future scope and deliverables of the MWBPP’s Systematic Preventive Maintenance (SPM) working group.   The working group serves to collect information regarding member states’ status in having an FHWA-approved SPM program.  The working group delivers a synthesis of member states’ participation in a program and any SPM-related information (e.g., contacts, agreements, guidelines, etc.) they are willing to provide on a triennial basis.  The last of which was released in November 2016 and is available through a link on the “MWBPP Working Group” page of the TSP2 Bridge Preservation website.

Those in attendance agreed the working group’s scope and deliverable were still relevant, as some member states were still working on developing or improving their SPM program and the information provided was of benefit to them.  In addition, attendees expressed their interest in a list of potentially eligible SPM activities – possibly ones preapproved by FHWA for inclusion in an SPM program.

Additional discussion within the group involved guidelines, processes, and equipment used to perform SPM activities with in-house forces and specifications for performing SPM activities through contract under an SPM program.

Deterioration Modeling: Fouad Jaber (chair), Nebraska DOR

Fouad Jaber with Nebraska DOR

12 people attend the working session.  The discussion went in the direction of continuing this effort.  Fouad will contact member states to find out their practices and needs for deterioration models.  We may create a pooled fund to address MWBPP State needs and bridge the gap between BrM and states practice. A survey will help focus the effort to what is needed.  The National efforts (BRM and LTBP) as well as individual state tools will be considered.  Hooman (Rutgers) from the LTBP will help with access to the LTBP Portal.   The survey will also identify the appropriate person in each state that we should coordinate with.  We may use pooled fund to reduce the data.  There will be a conference call in near future with Working Group to set up the survey

 

LINKAGE:

https://tsp2bridge.pavementpreservation.org/midwest-mwbpp/action-committees/

Emphasis on Case Studies at the MWBPP Meeting in Early November

Author: Lorella Angelini, Angelini Consulting Services, LLC

Bridge preservation case studies will be featured at the 2017 Midwest Bridge Preservation Partnership (MWBPP) meeting held at the Marriott City Center in Minneapolis, MN on November 6-8. The meeting will also focus on actions for deck and joint preservation and emergency response procedures for exceptional events, such as flooding, bridge hits and fire.

Bridge preservation practitioners attending the meeting represent the States that are part of the Midwest TSP2 Partnership region: Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, Oklahoma, South Dakota and Wisconsin. At the meeting preservation practitioners from DOTs and other owners will be interacting with contractors, consultants, academia and manufacturers that have a stake in bridge preservation in the Midwest region. Manufacturers will also have an opportunity for showcasing their products and technologies.

As with all TSP2 Bridge Preservation Partnership meetings, time will be dedicated to round tables where owners, consultants, academia, manufacturers and contractors can exchange information related to their experience with bridge preservation, underscoring challenges and solutions for extending the service life of concrete and steel bridges.

MWBPP mission is to provide a platform for bridge preservation practitioners to exchange, promote and advance best practices, new technologies and innovation in the areas of highway bridge management, inspections, preservation and maintenance.

For information please contact Darlene Lane at 517-432-8220 and email hidden; JavaScript is required

LINKAGE

2017 MWBPP Annual Meeting

Deck Preservation and Retaining Systems are Key Topics at the Upcoming NEBPP in NJ

Author: Lorella Angelini, Angelini Consulting Services, LLC

In less than two months, on September 11-13, the Northeast Bridge Preservation Partnership (NEBPP) meeting is scheduled to take place in New Brunswick, NJ. The meeting encompasses four sessions: deck preservation, research needs, case studies and retaining systems.

Over 150 bridge preservation practitioners specialized in maintenance and repair of concrete and bridge structures will be gathering in New Brunswick from the States that comprise the North-East region: Connecticut, District of Columbia, Delaware, Massachusetts, Maryland, Maine, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont. In addition to representatives from the owners, the meeting will also bring together contractors, consulting engineers, academia and manufacturers, who can showcase their innovation in products and services.

As with all TSP2 Bridge Preservation Partnership meetings, time will be dedicated to round tables where participants have the opportunity to exchange information and discuss practices that extends the service life of bridges.

Through the free and open exchange of ideas and information, the NEBPP’s mission is to better serve those who use the northeast transportation system. NEBPP strives to use innovation, new ideas, new products, and the combined experience of participant States to make bridge maintenance procedures and repairs the best that can be provided.

For more information please contact Darlene Lane at 517-432-8220 and email hidden; JavaScript is required

LINKAGE

https://tsp2bridge.pavementpreservation.org/northeast-nebpp/annual-meetings/2017-2/

Is the Practice of Bridge Preservation Heroic?

Author: Lorella Angelini, Angelini Consulting Services, LLC

A recent article published in The New Yorker magazine draws a parallel between the practice of incremental care in medicine and the preservation of bridges and infrastructures.   

The author, Atul Gawande, characterizes these two practices, incremental care and preservation, as “heroism of the incremental”. They are both based on the concept of implementing policies that focus on a steady flow of repetitive actions rather than reacting on short notice to specific and often dramatic problems. The incremental approach has been proven to be economical and effective, especially in providing long term benefits. The author points out that with today’s technology, incremental practices can take advantage of the latest available tools, especially in the areas of tracking, planning and communication. At the same time Gawande underscores the fact that incrementalism is chronically lacking of funds, which may be related to the fact that its approach is not considered “heroic”, meaning that it does not produce “immediate and visible success”.  

I cannot be more in agreement with the idea of incrementalism as it is described in the article. Incrementalism is based on a different mind-set than the reactive approach usually driven by an emergency. But it is still “heroic”. It only requires another type of hero, one far from the limelight, who works day after day to either provide care for people or maintenance to structures.    
http://www.newyorker.com/magazine/2017/01/23/the-heroism-of-incremental-care

The ECC Bendable Concrete

Author: Lorella Angelini, Angelini Consulting Services, LLClorella

Recently, CNN aired a report about America’s crumbling infrastructures. One of the topics was the so-called “bendable concrete” that was presented as an innovative solution that could extend the service life of US bridges.

Bendable concrete, officially called Engineering Cement Composite (ECC), has been developed over the last 10 years by Prof Victor Li, Civil and Environmental Engineer at Michigan University, Ann Arbor, MI. ECC is designed to overcome the inherent brittleness of concrete by having high tensile ductility and the ability to self-heal tight cracks. Its ductility allows constructing safer concrete structures that bend under extreme loads but do not break.  Crack control and self-healing provide higher concrete durability in a variety of environmental conditions.

ECC has been applied in Japan for a bridge deck that it is expected to last 100 years despite severe cold weather environmental conditions and limited thickness (2 inch) of the slab. The properties of ECC concrete allow structural elements to be designed with reduced dimensions and thus can provide significant cost savings to the owners by offsetting current ECC cost by volume, which is approximately 3 times higher than ordinary concrete.

ECC was also used for bridge deck construction in Michigan on Interstate 94. The application has been closely monitored by the University of Michigan and the Michigan Department of Transportation.

In 2015 ECC won the prestigious Construction Industry Council (CIC) Innovation Award with ECC.  CIC, which is based in Hong Kong, promotes sustainable innovation for the construction industry.

 

LINKAGE:

Read CNN news article: ”America’s infrastructure: Beams disintegrating under bridges”

http://www.cnn.com/2016/05/25/politics/infrastructure-roads-bridges-airports-railroads/

 

Watch ECC bendable concrete’s videos:

https://www.youtube.com/watch?v=FW3U3-7Qr_I

https://www.youtube.com/watch?v=dHGrAVS6UUQ

https://www.youtube.com/watch?v=TUxXzjzan5k

 

Participate in LinkedIn discussion about “bendable concrete”

www.linkedin.com/hp/update/6143804673406042112

 

Participate in Twitter discussion about America’s crumbling infrastructures

https://twitter.com/cnnpolitics/status/735574215210979328

 

Read ECC Wiki page

https://en.wikipedia.org/wiki/Engineered_cementitious_composite

 

Learn about CIC and its Innovation Award

http://cicinnovationaward2015.hkcic.org/en/home

 

Healer-Sealers for the Protection of Bridge Decks

lorellaAuthor: Lorella Angelini, Angelini Consulting Services, LLC

It is well-known that innovation represents one of the key elements for a successful bridge preservation strategy. An interesting innovation technology for bridge deck protection entails the so called healer-sealers. These are very low viscosity liquid-applied resins that penetrate by gravity into the hairline cracks and surface pores of concrete with the result of preventing infiltration of water and contamination by chlorides.

Different healer-sealer technologies are available, such as, Methyl Methacrylate (MMA), High Molecular Weight Methacrylate (HMWM ), epoxy and polyurethane. They all have in common an application method that consists in cleaning and opening the concrete surface, flooding it with the resin, and broadcasting aggregate (mainly sacrificial) before the resin starts setting. Performance properties vary between the different technologies as outlined in the snapshot information reported below. This information, which provides a general guideline about the technologies, is taken from technical data guides of a selection of brands that are present in the bridge preservation environment.

In comparison with other bridge deck protection solutions, healer-sealers are economical technologies both in terms of material and labor. This affordability should make it easy to apply healer-sealers over new decks. However, in the majority of cases, they are applied on an already contaminated deck after a few years following the completion of bridge deck construction, which in turn generally reduces their effectiveness.. For best performances, healer-sealers should also be re-applied periodically, on average every 5-10 years depending on the rate of of deck surface deterioration by traffic.

High Molecular Weight Methacrylate (HMWM)

  1. Viscosity: <25 cPs
  2. 100% solids
  3. Elongation: 5 – 30%
  4. Compressive strength: 3,000 – 8,000 psi
  5. Tensile strength:  500 – 1500 psi
  6. Aggregate should be placed within 15 – 20 minutes of resin application
  7. Application temperature (ambient):  50 – 100
  8. Traffic reopening:  4 – 8 hrs. after application (depending on ambient temperature)
  9. Flash Point > 200 °F

Methyl methacrylate (MMA)

  1. Viscosity: <5 – 10 cPs
  2. 100% solids
  3. Elongation: 4.5 – 5%
  4. Compressive strength: >12000 psi
  5. Tensile strength: > 8000 psi
  6. Aggregate should be placed within minutes of resin application
  7. Application temperature (ambient): 20 – 105 (with accelerator for low temperatures)
  8. Traffic reopening: 1 hr after application (depending on ambient temperature)
  9. Flash Point >50 °F

Very Low Viscosity Epoxy

  1. Viscosity: 100 cPs
  2. 100% solids
  3. Elongation: 10%
  4. Compressive strength: 8000 – 12000 psi
  5. Tensile strength: > 7000 psi
  6. Aggregate should be placed within 20 – 30 minutes of the resin application
  7. Application temperature (ambient): 40 – 90
  8. Traffic reopening: 6 hrs after application (depending on ambient temperature)
  9. Flash Point >200 °F

Ultra-Low Viscosity Epoxy

  1. Viscosity: 40 cPs
  2. 75% solids
  3. Elongation: 50%
  4. Tensile strength: 2500 psi
  5. Aggregate should be placed within 15 minutes of resin application
  6. Application temperature (ambient): > 50
  7. Traffic reopening: 4 hrs. after application (depending on ambient temperature)
  8. Flash Point:  > 100

Polyurethane / Polyurethane- hybrid

  1. Viscosity: 12-16 cPs
  2. Elongation: < 10%
  3. Compressive strength: 3000 psi
  4. Tensile strength: 4500 psi
  5. Aggregate should be placed immediately after resin application
  6. Traffic reopening: 10 – 90 minutes after application (depending on ambient temperature)
  7. Application temperature (ambient):  20 – 100
  8. Flash Point : >200°F

There a number of publications and research reports about healer-sealers. Some of them include a comparison with silane sealers.  A few links are reported below.

From Minnesota DOT:

http://www.dot.state.mn.us/research/TS/2014/201434.pdf

From Oregon DOT:

https://www.oregon.gov/ODOT/TD/TP_RES/docs/reports/2010/crack_sealer.pdf

From Colorado DOT:

https://www.codot.gov/programs/research/pdfs/2014/sealers.pdf/

From Kansas DOT:

http://ntl.bts.gov/data/letter_ak/KS-98-4.pdf

From Utah to Panama Following a Humanitarian Call

Author: Lorella Angelini, Angelini Consulting Services, LLC

Do engineers have a warm heart? Yes and a generous one!
Behind their notoriously serious face, engineers have a generous attitude, which responds to their social call. At the core of their work there is a dedication to servicing the communities by designing sound structures that are safe and last long, even in difficult environmental conditions.

A story that underlines engineers’ generous attitude is being written by Joshua Sletten, bridge management engineer with Utah DOT. Leaving temporarily aside his responsibility of managing bridges across the state, Joshua has taken the commitment of building a 150-foot suspension bridge in Luna, Panama, thus replacing the rickety, life-threatening bridge that is currently used by the local population.

Joshua will lead a 10-person volunteer team with “Bridges to Prosperity”. This non-profit organization based in Colorado has an inspiring mission, which entails providing isolated communities with access to essential health care, education and economic opportunities by building footbridges over impassable rivers.

LINKAGE
Information and a video about Joshua Sletten project in Panama can be seen here:
http://www.ksl.com/?sid=38846775&nid=148
Information about Bridges to Prosperity non-profit organization can be found here:
http://bridgestoprosperity.org/
https://www.facebook.com/BridgestoProsperity
https://en.wikipedia.org/wiki/Bridges_to_Prosperity

Current and Futuristic Methods to Seal Concrete Cracks

Lorella Angelini
Author: Lorella Angelini, Angelini Consulting Services, LLC

There are many ways to design concrete mixes. Different types of ingredients and dosages can be used in various combinations so as to respond to construction and specification requirements. However all concrete mixes share one basic, common denominator: they should not develop cracks, even under stress conditions.

Not only are cracks aesthetically unpleasant, they are also very detrimental since they provide a way of entry for contaminants, such as chlorides and sulphates, into concrete. Once it penetrates into the cracks, water alone can cause concrete spalling by freeze-thaw cycles.

Between the technologies for permanently sealing cracks in concrete, epoxy resins are widely used, especially for structural cracks. Epoxies have great adhesion to concrete, high compressive and tensile strength, volume stability, and are available in a variety of formulations for different types of applications. For example, wall cracks can be sealed by injecting epoxies at low or high pressure, preferably moving from the bottom to the top of the wall. Other types of epoxies with low or ultra-low viscosity can be used to seal cracks in concrete decks or pavements. In this case the material is fed into the cracks by gravity. This application method is also used with HMWM (High Molecular Weight Methacrylate) or MMA (Methyl Methacrylate) resins that have a level of viscosity so low that can be compared to water.

In the future these proven technologies may have to confront with a new, experimental method to seal concrete cracks that is based on the use of natural bacteria. By introducing bacteria into concrete cracks, simply using a garden sprayer, long, thin cracks can be sealed in a relatively short time with the limestone compound produced by the bacteria, when these organisms come in contact with water. More information about the sealing mechanism is reported in the links. The Netherlands and the UK appear to be on the leading edge of this exciting development program.

Epoxy injection:

http://www.concretenetwork.com/concrete/crack_injection/basicsteps.html

http://www.concreteconstruction.net/repair/epoxy-injection-for-cracked-concrete_o.aspx

https://www.concrete.org/store/productdetail.aspx?ItemID=503707&Format=DOWNLOAD

Gravity fed epoxies:

http://docslide.us/documents/crack-repair-by-gravity-feed-with-resin.html

Gravity-fed MMA:

http://trrjournalonline.trb.org/doi/10.3141/2202-10

Bacteria-healed cracks:

http://digg.com/video/concrete-bacteria-heals-cracks

http://www.nbcnews.com/id/40201539/ns/technology_and_science-green_innovation/t/designer-bacteria-can-heal-cracks-concrete-buildings/#.VujQVeYk3HA