Pavement preservation using new lithium densifier wear resistant surface hardener for new construction and for extension of service life in concrete pavements.

1. PRESERVING CONCRETE PAVEMENTS
LITHIUM DENSIFIER WEAR RESISTANT SURFACE HARDENER FOR
NEW CONSTRUCTION TINNED, DIAMOND GROUND, GROOVED OR
SHOTBLASTED SURFACES.
Claudio Manissero
President, ChemCognition LLC
ACI Carolinas Mtg
May 9,2018

2. Introduction (From ACI 201.2-R16)
• Abrasion resistance of concrete is defined as the ability of a surface to resist being worn
away by rubbing and friction. Abrasion of floors and pavements can result from production
operations or vehicular traffic.
• While focus of ACI 201.2-R16 is on flooring, the principles are the same in load bearing
surfaces such as pavements and bridge decks.
• The abrasion resistance of concrete is a progressive phenomenon. Initially, the resistance is
related to compressive strength.
• As softer paste wears away, the particles of fine and coarse aggregate are exposed,
abrasion and impact will cause additional degradation that is more related to the paste-to-
aggregate bond strength and the relative hardness of the aggregate than to the compressive
strength of the concrete.
• Because abrasion occurs at the surface, it is critical that the surface strength be maximized.
• Lithium densifiers have been shown to be an effective treatment for flooring. The new
development provides formulation modifications that allow application of the technology to
exterior load bearing surfaces.

3. Benefits
• Friction/Abrasion resistance has been identified by FHWA and DOT’s to be a very important
parameter to address as it has been recognized as being related to:
− Premature deterioration due to surface degradation (durability/sustainability and economic
impacts)
− Safety issues with polishing and surface degradation with loss of skid resistance due to
polishing.
− Degradation of surface tined/diamond ground surfaces
• Laboratory testing and field evaluations through a Pooled Fund study have shown lithium-silicate
based densifier systems to be effective in hardening the surface and addressing issues regarding
friction/abrasion resistance.
• There are no national standards or protocols adopted in the industry so each DOT has developed
their own resulting in barrier to entry.
• There are other benefits to the technology that have been evaluated in the lab but not proven in
field yet:
− Deicer induced scaling
− Chloride penetration
− Freeze-thaw protection
− ASR related deterioration
− Added flexibility in use of local aggregates

4. Technology Overview
• The chemical process of densification involves a reaction between the concrete
and a densifier that results in a denser, thus harder, surface.
• Lithium silicate has been shown to react with calcium hydroxide produced from
cement hydration to form a tight, hard calcium/lithium silica hydrate (CLSH) that
precipitates out and hardens in the pore solution.
• The lithium silicate stabilizes the silicate in solution allowing it to penetrate in
the surface where it reacts with the calcium to form the CLSH matrix.
• CLSH results in a protective layer that is insoluble and increases bond strength
between paste and aggregate.
• Lithium displaces sodium and potassium in the pore solution providing additional
protection against ASR which at microscopic level affects the paste to aggregate
bond (loss in static modulus)
• Chemistry has been proven in widespread use in concrete flooring.
• The fully formulated lithium silicate densifier includes additive to improve
penetration, catalysts to speed up the reaction, and water repellency that
internally dehydrate the formed CLSH matrix.

5. Beneficial Effects
• Field studies conducted by individual state DOT’s on pavement preservation have
identified the issues and the costs associated with rutting , friction loss, spalling and
scaling, and control joint sealant failures. These represent factors that can
significantly affect ability to meet design service life as well as safety.
• Some states have adopted partial preservation techniques to extend pavement life
but no standard protocols have been established. No holistic approach has been
taken to address all these issues as being related to surface abrasion/durability.
• New lithium based technology has been shown to increase surface density and
hardness and when applied in conjunction with surface abrasion and profiling by
processes such as traditional and NGEN Diamond Grinding and shotblasting initial
studies have shown:
− Reduced “wear” and “abrasion” caused by mechanical erosion and traffic loads
− Improved efficacy of “friction” treatments – a) post treatment on new pavements, and b) treatment after
mechanical scarification to improve skid resistance.
− Life cycle cost analysis conducted by D. Gransberg (Iowa State Univ.) and D. Pittenger (Univ. of
Oklahoma) have concluded that the lithium based technology provides life cycle cost advantages over
existing preservation practices. [Research, Development, and Practice in Structural Engineering and
Construction, Vimonsatit, V., Singh, A., Yazdani, S. (eds.) ASEA-SEC-1, Perth, November 28–December
2, 2012]

6. Ongoing Testing Caltrans
CALTRANS / California State University, Chico / Study - abrasion loss
showing wear distress after one year comparing treated and un-treated shot-
blasted new construction surface (I80)

7. Caltrans Study
https://www.dropbox.com/l/scl/AADSbGtoIW2ZR-orW-TLDuY4Jzvkp8mt708

8. Ongoing Testing - Caltrans
CALTRANS / California State University, Chico / Study image
showing visual distress after one year comparing treated and un-
treated shot-blasted new construction surface.

9. Ongoing Testing – OK DOT
EVALUATION OF A CHEMICAL HARDENING PROCESS TO INHIBIT AGGREGATE
ABRASION AND POLISHING - University of Oklahoma / NCAT Research
Dominique M. Pittenger, PhD, AC University of Oklahoma College of Engineering
Sponsored by Oklahoma Department of Transportation

10. Ongoing Testing - California State University,
Chico CP2 ( Pavement Preservation Center)
The purpose of the study is to evaluate
the abrasion resistance of various concrete
surfaces using a given surface hardener.
This study includes laboratory testing,
data analysis, reporting, and coordination
with industry. The primary objectives are:
• Determine the abrasion resistance for
treated and untreated cement mortar
surfaces using California Test 550.
• Determine an optimal application rate
of surface hardener on cement mortar
which results in the least amount of
material abrasion.

11. Ongoing Testing – Brigham Young U.
Evaluation of Lithium Silicate and Silane Applications for Sealing Concrete
Barrier Walls Exposed to Chloride-Based Deicing Salts
W. Spencer Guthrie, Ph.D., M.ASCE Brigham Young Univ. Provo, Utah, USA

12. Cost Cycle Analysis

13. Additional Potential Benefits
The following are potential added benefits requiring further
study:
• Freeze-Thaw Resistance
• Anti-scaling Protection
• Chloride penetration (corrosion protection)
• Joint life
• ASR protection
Potential for Technology to be combined with curing
• Studies performed at TTI (Texas A&M) and at UF have indicated that the
lithium densifier can be effective curing agents that meet and exceed
parameters from ASTM C 156-98, reducing shrinkage cracking without
affecting densifying/hardening properties.
• Further field studies needed to prove concept.

14. Ongoing Testing – Tourney Consulting
ASTM C672 Modified Test Method for Scaling Resistance of Concrete
Surfaces Exposed to Deicing Chemicals.
Evaluation of Troweled Concrete Surface Sealed with Treatment.

15. Significance of Technology
• Pavement Preservation a key program under the FHWA Innovation
program and AASHTO
• Being promoted by IGGA, National Center for Pavement
Preservation and the Foundation for Pavement Presentation
• First phase Pooled Fund Study wrapping up
• Issue has become an International issue – Pavement Preservation
and Recycling Summit 2018 had over 1000 attendees.
• FHWA Innovation has funding available for test sections and are
seeking a group of states to participate. Each will get $ 100 k for
the demos and program will be monitored under LTPP.
• States that have expressed interest: Mn, MI, OK, MO, IL, WA, CA,
TX - Will the Carolinas participate?

17. Issues to be Addressed
• Lack of standard protocols/decision trees for pavement preservations that
can be used to evaluate technologies.
• Lack of Standard testing protocols universally applicable (most states
have own preferred testing methods so technology not easily
transferable).
• Technology awareness regarding options for surface preservation that
start during construction.
• Lack of life cycle cost understanding and implementation that include
surface preservation (durability and safety)
• Present micro / macro texture applications wearing faster than projected
and negatively impacted by deicing salts. Joints also affected.
• Technology can reduce deicing salt damage by 94% and can extend
friction surface life 25-40%.
• Basic technology proven in flooring since 2000 unknown in transportation

19. Contact Information
For More Information
Contact
Claudio Manissero
President
ChemCognition LLC
claudio@Chemcognition LLC
+01 - 704-907-5463 (US)