Engineering
Colloidal Silica for Concrete
Concrete permeability is the enemy of long-lasting concrete. Post-set applied colloidal silica can reduce permeability to near zero, keeping out water and contaminants.
Field of Expertise
Concrete materials science
Expertise
Mr. Alex Brent Rollins has more than 25 years’ experience as a concrete materials specialist, working on a wide variety of residential, commercial, infrastructure, and government projects spanning all facets of concrete construction. Additionally, he has published several peer-reviewed papers in concrete technology and has performed forensic investigations of concrete globally. Mr. Rollins holds a BA degree in Homeland Security from Keiser University in Fort Lauderdale, Florida as well as a post-baccalaureate certificate in Terrorism Studies from St. Andrews University in the U.K. This education along with his experience in his field of study combines to provide a complementary basis of analysis in the critical infrastructure protection sector. Projects performed include risk assessments of state highway transportation networks and nuclear power and spent fuel storage on three continents. Current Positions Held: Vice President of Business Development and R&D, Spray-Lock Concrete Protection Chattanooga TN 2017- Owner/CEO Alex Brent Rollins, Inc. Dalton, GA 2015- Key expertise: • Concrete aggregate particle packing behavior • Concrete rheology • High performance concrete • Concrete permeability and porosity • Concrete life cycle modeling • Particle image analysis • Hazard, Threat, Vulnerability, Consequence, and Risk Analysis • Concrete curing • Temperature effects in mass concrete • Long term durability of concrete • Fiber reinforced concrete • Recycled materials in concrete • Concrete forensic investigation • Ready mixed concrete operations and quality control EXPERIENCE The University of Tennessee at Chattanooga (UTC) Director, Civil Engineering Materials Research Laboratory Chattanooga, TN 2010-2017 Mr. Alex Brent Rollins joined Civil Engineering at UTC in March 2010. His research and teaching interests include civil engineering materials, recycled content in concrete, high performance concrete, engineering forensics, image analysis of particles, and infrastructure protection. Mr. Rollins' research activities produced the introduction of four new products to the marketplace, all involving forms of recycled material in concrete. During Mr. Rollins' time at UTC, his research efforts brought in approximately one million dollars in funding. Key service activities include assisting with instructive laboratory tours for Gear Up and other community members, ASCE activities, and serving as a Trusted Agent of the UTC Emergency Operations Center. Protecht Consulting, LLC., Vice President & Principal Chattanooga, TN, 2008 – 2016 Protecht Consulting was an engineering consulting and contract research firm with over two decades of experience in resolving problems faced by the a variety of industries. Protecht Consulting specializes in engineering forensics, statistical quality control, pavement design, structural design, retaining wall design, facility security assessments and improvements, quality management, particle image analysis, bioremediation, and new product development. Mr. Rollins has performed consulting projects in the U.S., Canada, Chile, Costa Rica, France, Puerto Rico, Spain, Scandinavia, the U.K., and the Middle East. As of 2016, Mr. Rollins has founded his own company, Alex Brent Rollins, Inc., which continues the previous work of Protecht. Example Activities: Impact echo for void detection and thickness, chloride diffusion in concrete modeling, pharmaceutical image analysis, concrete site forensic investigation, all-hazards risk assessment, facility security hardening, new product delivery to market, quarry evaluation, waste material reuse, retaining wall design, maritime construction planning. Ready Mix USA Division Quality Control Manager Chattanooga, TN, 2002 – 2010 605 Hudson Rd. Chattanooga, TN 37405 Ready Mix USA (now a division of Cemex) is a world leader in the production of ready mixed concrete. During his time as Division Quality Control Manager, Mr. Rollins managed a group of up to three field technicians, and was ultimately responsible for the quality of concrete in the Tri-States Division, averaging approximately 250,000 cubic yards per year production. EXPERIENCE (continued) Example Activities: Concrete mix development, raw materials evaluations, maturity method of compressive strength prediction, field testing of concrete, laboratory testing of concrete and aggregates, certified concrete technologist in Alabama, Georgia, and Tennessee, mass concrete design, fire resistant concrete design, impact resistant concrete design, field forensic evaluations of concrete, concrete plant automation troubleshooting, concrete rheological adjustments. Notable Projects: Volkswagen of America (Chattanooga, TN), Alstom Power (Chattanooga TN) Sequoyah Nuclear Plant (Chattanooga, TN), Tennessee Aquarium (Chattanooga, TN), Georgia Power Plant Hammond (Rome, GA), Blue Cross/Blue Shield of Tennessee (Chattanooga, TN), One North Shore (Chattanooga, TN), Shaw Industries (Dalton, GA), Duke Power (Dalton, GA), blast resistant concrete design (military installations). North Georgia Ready Mix Plant Manager, Building Materials Manager, Area Operations Manager Dalton, GA, 1990-2002 419 Selvidge Street Dalton, GA 30720 North Georgia Ready Mix (purchased in 2002 by Ready Mix USA) was a regional leader in the production of ready mixed concrete. During his time as Area Operations Manager, Mr. Rollins managed a group of up to eighty concrete mixer drivers and eight concrete plant managers. During this time, Mr. Rollins was responsible for the economic productivity of the operations in all facets. Example Activities: Concrete logistics and dispatch, DOT driver qualification files, accident reporting, variable cost control, raw material evaluation and selection, customer service, forensic investigation of concrete, all facets of scheduling and troubleshooting concrete plants and mixer trucks. Notable Projects: Shaw R&D Building (Dalton, GA), Mount Vernon Mills (Summerville, GA), Multiple carpet mills & big box stores (from Chattanooga, TN to Rome, GA). Cc EDUCATION & HONORS Keiser University, Fort Lauderdale, FL BA, Homeland Security, 2009 University of St. Andrews (Scotland) Post Baccalaureate Graduate Certificate, Terrorism Studies INVITED LECTURES "Colloidal Nano-Silica as a Concrete Treatment: Laboratory and Case Studies," Total E&P and AREVA, Paris, France Jan. 22, 2016. "Emerging Trends in the Concrete Industry," Discussion Panel, Middle East Concrete Conference, Dubai, UAE Nov. 22-24, 2015. "Colloidal Nano-Silica as a Concrete Treatment: Laboratory and Case Studies," Middle East Concrete Conference, Dubai, UAE Nov. 22-24, 2015. "Blast mitigation and line-of-sight restriction recommendations for a municipal courthouse," Dalton, Georgia Sept. 4, 2015. "Effects of Radiation on the Microstructure of Portland Cement Concrete," University of Tennessee at Chattanooga Nuclear Engineering Program, Aug 27, 2015. "Self Consolidating Concrete" (8-hour seminar) Tennessee Department of Transportation, Aug. 17,26, 31 and Sept. 9 2015. "Evaluation of Earthquake-Damaged Concrete Structures for Non-Engineers," TN-1 DMAT (Disaster Medical Assistance Team), Knoxville, TN 7-9-15. “Blast Mitigating Concrete”, American Concrete Institute, Georgia Chapter. Atlanta, Ga. March 22, 2013 “Concrete on the Jobsite: Beyond the Testing” 2012, Industry Seminar, UTC “UTC’s Civil Engineering Materials Research Laboratory: Two Years of Progress” 2012, Industry Seminar, UTC “Understanding Religious Extremism” 2012, (9-week course), church groups, Dalton, Georgia “An Introduction to Chemical Admixtures in Portland Cement Concrete” AIA/Terracon Chattanooga, TN Dec. 20, 2011. “Nondestructive Testing Methods in Civil Engineering Applications” American Concrete Institute, Georgia Chapter. Atlanta, Ga. Oct. 22, 2010. “Ready Mixed Concrete in the U.S.” Annual Meeting of the Former Soviet Republics Civil Engineering Community sponsored by the U.S. Dept. of State 2009 & 2010, Chattanooga, TN. “Predicting Concrete Compressive Strength by Maturity Method” EMJ Corporation Annual Project Managers Meeting. 2008, Chattanooga, TN. Meeting, 2005. Dalton, GA. “Portland Cement Concrete Materials and Practice in Europe” BASF/Master Builders Annual General Session Meeting, Cleveland, OH 1999 ACTIVITIES RESEARCH GRANTS “Establishing Global Greenfield Ready Mixed Concrete Operations” Unicon Beton Corporate Managers’ Meeting, Aalborg, Denmark 1998 American Society of Civil Engineers (ASCE) ACI International ASTM - American Society of Testing & Materials PIANC - An international organization concerned with port sustainability & security Peer Reviewer, ASTM special publications, ACI Materials Journal "Modular Curtain Walls" Precast/Prestressed Institute & Oak Ridge National Laboratory 2016-2018. "Effects of Colloidal Nano-Silica on Roller Compacted Concrete" 2016. With Dr. Joseph Owino and Dr. Ignatius Fomunung "Effects of Biologically Generated Sulfuric Acid on Concrete Treated with Colloidal Nano-Silica" 2015-2016 "Development of Class P-SCC (Self-Consolidating Concrete) and Class A-SCC Concrete Mixtures," With Dr. Joseph Owino (PI), Dr. Ben Byard, Ammar El Hassan, and Mohamed Khalafalla. Tennessee Department of Transportation 2013-2015. “All-Hazards Risk Assessment of Critical Transportation Infrastructure in the State of Tennessee” Tennessee Department of Transportation, August 2013- present “Water Vapor Transmission Reduction of Portland Cement Concrete Treated with Colloidal Silica” June 2013-present “Cement Paste Demand in Fractioned Coarse Aggregate and Traditionally- Graded Aggregate Portland Cement Concrete” May-June 2013 “Using Imaging Analysis to Measure Surface Characteristics of Roller Compacted Concrete” Nov. 2012- present with Dr. Heather Brown, MTSU “Behavior of Unburned, Unprocessed Rice Husks in Portland Cement Concrete” Nov. 2012 – present “Aircraft Deicing Chemical Penetration Resistance of Portland Cement Concrete Treated with Colloidal Silica” Oct. 2012 “Utilization of Spore-Forming Bacteria in Self-Cleaning Pervious Concrete Pavement” July 2012- with Drs. Mbakisya Onyango, Tricia Thomas, and Henry Spratt “Resistance to Acid Attack of Concrete Treated With Colloidal Silica” March 2012 “Resistance to Petroleum-Based Fire of Concrete Treated With Colloidal Silica” “Evaluation of a Geosynthetic Fabric for Increasing Exfiltration Rates of Pervious Concrete” Oct. 2011-Dec. 2012 “Optimized Fractioned Coarse Aggregate in Portland Cement Concrete” June 2010 – Feb. 2011 PRINCIPAL FORENSIC INVESTIGATIONS (Consulting) PRINCIPAL FORENSIC INVESTIGATIONS (Consulting - Cont.) Evaluation and Design of Repair Strategies for Port Facilities (2016, current), Port of Marseille, France Evaluation of Potential Repair Strategies for Active Gold Mine Shaft (2016, current) Cape Town, South Africa Evaluation of Potential Repair Strategies for Military Underground Aviation Fuel Storage Tanks (2016, current) Various Locations, France Acoustic Evaluation of Hospital Radiation Oncology Shielding Concrete (2015) Port of A Coruna, Spain (2014) Corrosion and chloride diffusion investigation Lily Pharmaceutical, San Juan, Puerto Rico (2014) concrete surface discoloration investigation Port of Marseille, France (2014) Sea wall investigation Image Analysis of Pharmaceuticals to Determine Particle Size Distribution (ImageJ) - with Dr. Bryan Ennis (2014). Proyecto Eolico Valle Central Wind Turbine, Costa Rica (2011) Cracking Mitigation Corrosion potential investigation (assisting) – The Passage, Chattanooga, TN (2009) Nondestructive Compressive Strength Verification of Airport Parking Deck (impact-echo and penetration resistance) – Huntsville, AL (2009) Impact Echo void location – Chickamauga Dam, Chattanooga, TN (2009) Impact-Echo Yield Verification of Semi-Lightweight Elevated slab – PUBLICATIONS Rollins, A.B.; Owino, J.O.; Fomunung, I. “Improving Hardened Properties of Portland Cement Concrete with Surface-Applied Colloidal Nano-Silica” peer- reviewed, fib Cape Town, South Africa 2016. Rollins, A.B. " Utilizing Colloidal Nano-Silica as Treatment for Concrete in Salt Water Ports: Laboratory Chloride Diffusion, Life Cycle Modeling, and Port of Marseille Test Case,", peer-reviewed, ASCE/PIANC Ports 2016, New Orleans, LA. Rollins, A.B.; Collet, Pascal; Andres, Valery "Concrete Porosity Reduction by Colloidal Silica Nano Technology," peer-reviewed, CONSEC 2016, Lecco, Italy. Sanford, Charles; Onyango, Mbakisya A.; Thomas, Tricia A.; Jones, Frank; Rollins, A.B. “Evaluation of Cleaning Methods of Pervious Concrete Pavement” Conference Proceedings, July 2015. Fomunung, I., Owino, J, and Rollins, A.B. "Effects of a Wax Emulsion Admixture on Compressive Strength and Surface Characteristics of Roller Compacted Concrete," 2014 International Conference on Transportation in Africa Presented 12/19/14 Gaborone, Botswana. Ennis, Bryan; Rollins, A.B.; Ennis, Brandon; Pruitt, M.; Owino, J; Rickman, D.; Hannan, B; Lohn-Wiley, B.T. "On characterizing particle shape" presented at AIChE, Atlanta, GA Nov., 2014. Rollins, A.B. [software product] "Calculating cement paste demand and void content from particle size and shape data," Astec Industries Private Product, June, 2013. Rollins, Alex B. and Thrasher, Lee (1998) Ready Mix Operations. Middle Tennessee State University Press REFERENCES & OTHER References available on request. ACI Level I Field Technician Georgia Department of Transportation Concrete Technician Tennessee Department of Transportation Concrete Technician Alabama Department of Transportation Concrete Technician NRMCA Sustainable Concrete Technologist Member, Transportation Research Board (TRB) Standing Committee on Transportation Infrastructure Protection Peer reviewer for ACI Materials Journal Peer reviewer for ASTM Special Publications Member, PIANC Member, American Concrete Institute Member, ASTM C09 32 Homeland Security related certifications and certificates