REFERENCE & RESEARCH

UNI-GROUP U.S.A. is committed to product development and ongoing technical research to offer engineers, architects, and landscape architects new options in the design of interlocking concrete pavements. We've included a synopsis of a select number of research papers and articles from around the world. If you would like to order any of the research papers listed below, click here.

We also have a number of references relating to permeable and traditional interlocking concrete pavers from agencies and organizations such as the Environmental Protection Agency, Low Impact Development Center, National Association of Home Builders, Nonpoint Education for Municipal Officials and more. You may download these files from our Downloads page. We also provide an extensive list of informational links, articles and case studies for reference as well.

UNI ECO-STONE DESIGN GUIDE & RESEARCH SUMMARY
This comprehensive manual has recently been updated to 60 pages, covering all research available to date on the Eco-Stone^® Family of Permeable Pavers as well as a project list, design and construction guidance, specifications and maintenance and construction forms. You may download this guide or order a hard copy.

POROUS PAVEMENTS
Bruce K. Ferguson, FASLA, provides a comprehensive overview of all types of porous pavements in his new book, Porous Pavements, published by CRC Press, Boca Raton, FL. The book, at 600 pages is the first of its kind on the sole subject of porous pavements. The book includes information on porous pavement installation, pavement structure, hydrology, performance, and maintenance, as well as extensive references. It also includes 310 photos, charts, tables, and diagrams. The book is highly recommended for design professionals, developers, planning and environmental commissions, and to students.
You may order this book from Amazon.com.

PERFORMANCE EVALUATION OF PERMEABLE PAVEMENT AND A BIORETENTION SWALE
Tim Van Seters, Derek Smith and Glenn MacMillan, Toronto and Region Conservation Authority, Toronto, ON - 2007
Infiltration stormwater best management practices are gaining in popularity due to reductions in flow volume and temperature related impacts on nearby receiving waters. Permeable pavement and bioretention swales offer some of the most promising potential.  With these technologies, runoff is infiltrated into the soil naturally, reducing the need for treatment and eliminating the need for underground or site consuming detention facilities. This study builds and expands on the previous research in evaluating the effectiveness of Ecoloc^® permeable concrete interlocking pavers and bioretention swales for stormwater management under climate and soil conditions representative of watersheds in the Greater Toronto Area (cold climate areas).  The site for this study is located on a parking lot at Seneca College’s King Campus in the Township of King. The parking lot is often full during the school year, but is used less frequently during the summer, except during special events. Water quality and quantity were monitored. In addition, five older permeable pavement sites ranging in age from 3 years to 16 years were surveyed. Click here to download a copy of this report.

LONG-TERM IN-SITU INFILTRATION PERFORMANCE OF PERMEABLE CONCRETE BLOCK PAVEMENT
Dr. Soenke Borgwardt - 2006
Due to the entrainment of mineral and organic fines into the pores of porous concrete blocks or into the aggregates used in joints or openings, the reduction of water permeability can be assumed. Research results show that the infiltration performance decreases in the order of the power to ten after a few years. The study states moreover that the long-term in-situ infiltration performance and its observed decrease depend on the grain size of the aggregates used for joint filling. It is furthermore partly induced by the ratio of openings of permeable pavements respectively the pore size of porous concrete blocks. Despite the reduction in permeability rates after 10 years, it was demonstrated that the pavements were still capable of infiltrating virtually any design storm. Click here to download a copy of this paper.

MORTON ARBORETUM'S GREEN PARKING LOT
Andrew J. Sikich, P.E. and Patrick D. Kelsey, CPSSc/SC.
This paper was presented at the 2005 StormCon Conference in Orlando, FL. This paper details the low impact design features used at the Morton Arboretum in Dupage County, Illinois, a 1700+ acre outdoor museum that underwent a large-scale redevelopment of the visitor center, main entrance and parking lot. The project received a 319 Grant from the IEPA that was used to construct the best management practices within the parking part of the facility. Over 173,000 square feet of ECOLOC^® permeable interlocking pavers were used for the parking areas, along with another 32,000 square feet of UNI-Anchorlock^® solid interlocking pavers. Click here to download a copy of this report.

INTERLOCKING CONCRETE BLOCK PAVEMENTS AT HOWLAND HOOK MARINE TERMINAL
Walter E. Sieglen Jr, P.E. and Harald von Langsdorff co-authored this paper prepared for the ASCE Ports 2003 Exposition. Sieglen is the former Principal Civil Engineer for Design of Port Commerce Facilities of The Port Authority of New York and New Jersey. Sieglen was responsible for the design of both permeable (Ecoloc^®) and traditional (Anchorlock^®) interlocking concrete block pavements. This report details the design and construction process and includes photographs. Click here to download a copy of this report.

JORDAN COVE 2003 ANNUAL REPORT
This EPA Section 319 National Monitoring Program project is studying the impact of residential development on stormwater runoff quantity and quality, as well as the best management practices (BMPs) implemented to manage it. Dr. John Clausen and Jennifer Gilbert of the University of Connecticut Department of Natural Resources are co-authors of the report. UNI Eco-Stone^® permeable interlocking pavers were used for the cul-de-sac street and some of the driveways in the BMP section of the project. Click here to download a copy of this report. 

UNI-GROUP U.S.A. has sponsored two extensive North American research projects on the UNI Eco-Stone^® Permeable Pavement System:

TEXAS A&M UNIVERSITY
Over two years of research was conducted to develop guidelines for the design of pavements using the UNI Eco-Stone^® Concrete Paver. Testing was conducted on several test sections of UNI Eco-Stone^® installed at the TTI annex at the Riverside Campus of Texas A&M. Professor Dan Zollinger of the Civil Engineering Department was the coordinator of the project. A 48-page report, Drainage Design and Performance Guidelines for UNI Eco-Stone^® Permeable Pavement includes figures, tables and charts, as well as a step by step worksheet for engineers. Information is provided on runoff infiltration and its control and interaction with the performance of the pavement system. This manual is currently only available as a digital file - click here to order.

UNIVERSITY OF GUELPH 
On-going research at the University of Guelph is being conducted on UNI Eco-Stone^® with a focus on environmental factors and stormwater management. Topics being researched include pollutant filtration, thermal load reduction, and permeability renewal. Both laboratory and on-site testing has been conducted. Several theses have been published to date, with a book to be published by Professor William James in the near future. A list of titles is shown below. Download or order a printed copy of the Eco-Stone Design Guide and Research Summary for an outline of each thesis.

THE LEACHING OF POLLUTANTS FROM FOUR PAVEMENTS USING LABORATORY APPARATUS - Reem Shahin - 1994

EXPERIMENTAL INVESTIGATION OF THERMAL ENRICHMENT OF STORMWATER RUNOFF FROM TWO PAVING SURFACES - Brian Verspagen - 1995

DESIGN AND INSTALLATION OF TEST SECTIONS OF POROUS PAVEMENTS FOR IMPROVED QUALITY OF PARKING LOT RUNOFF - Michael Kaestner Thompson, P.Eng. - 1995

LONG-TERM STORMWATER INFILTRATION THROUGH CONCRETE PAVERS - Christopher Kresin - 1996

FEASIBILITY OF A PERMEABLE PAVEMENT OPTION IN THE STORM WATER MANAGEMENT MODEL (SWMM) FOR LONG-TERM MODELING - Craig Kipkie - 1998

RESTORATION OF INFILTRATION CAPACITY OF PERMEABLE PAVERS - Christopher Gerrits - 2001

Visit www.computationalhydraulics.com. for an extensive archive on SWMM related topics, stormwater Internet news, water resource links, and more.

WORLDWIDE ECO RESEARCH

INFILTRATION AND STRUCTURAL TESTS OF PERMEABLE ECO-PAVING
B. Shackel, J.O. Kaligis, Y. Muktiarto, and Pamudji
In laboratory tests conducted on UNI Eco-Stone^® in 1996 by Dr. Brian Shackel at the University of New South Wales in Sydney, Australia, measurements of water penetration under heavy simulated rainfall were studied, and the structural capacities of the paver surface was tested. A range of bedding, jointing, and drainage void materials was tested, ranging from 2 to 10mm aggregates. The best performance was achieved with a clean 2-5mm aggregate containing no fines. The use of ASTM C33 grading was found to be inappropriate where water infiltration is the primary function of the pavement. The experimental data showed that it was possible to reconcile the requirements of obtaining good water infiltration with adequate structural capacity that is comparable to that of conventional concrete pavers.

EXPERT OPINION ON UNI ECO-STONE - PEDESTRIAN USE 
Beurkhard Bretschneider - 1994
This report tested Eco-Stone^® for safety and walking ease under a pedestrian traffic application. Bicycles, wheel chairs, baby carriages, and foot traffic were tested. Ladies high-heel shoes were tested for penetration depth in the drainage cell aggregate materials. The finding showed that proper filling and compaction of the drainage cell materials was important for good overall performance.

EXPERT OPINION - IN-SITU TEST OF WATER PERMEABILITY OF TWO UNI ECO-STONEPAVEMENTS
Soenke Borgwardt - Institute for Planning Green Spaces and for Landscape Architecture - University of Hannover - 1994
Tests were performed on two Eco-Stone^® pavements of various ages at two different locations in Germany. A parking lot at the train station in Eldagsen was installed in 1992, while the Lenze Company parking lot in Gross Berkel was installed in 1989. The results showed the Eldagsen site was capable of infiltrating 350 l/sec/ha, and even after 60 minutes, absorbed more than 200 l/sec/ha. At the Lenze site, the pavement was capable of infiltrating 430 l/sec/ha, and after 60 minutes, 400 l/sec/ha. Although the comparison showed the older site had a higher permeability, tests showed the lower permeability values at  Eldagsen were the result of the existence of fines. 

UNI INTERLOCKING CONCRETE PAVER RESEARCH

APPLICATIONS FOR CONCRETE PAVING BLOCK IN THE UNITED STATES MARKET
By Raymond S. Rollings, Ph.D., P.E. & Marian P. Rollings, Ph.D., P.E. - 124 pages
Comprehensive review, analysis, and synopsis of international information on interlocking concrete block pavements (with emphasis on the United States). Includes history, paver characteristics, design considerations, applications, design methodology, and specifications. Includes, tables, figures, charts, and photographs. This manual is only available in print form - to order, click here.

DYNAMIC LOAD BEARING TESTS ON BLOCK PAVEMENTS 
F. Wellner and T. Gleitz - 1996
Proceedings, Fifth International Conference on Concrete Block Paving, Tel Aviv, Israel. Dynamic tests on black pavements were carried out on a 1:1 scale at the Chair of Road Construction at the Technical University of Dresden. The pavements were stressed with a sustained depression pulsating stress via a 30-cm diameter steel load plate. The elastic and plastic deformations were measured during the period of dynamic load, and in addition, static load measurements were taken. The pavement types varied according to shapes of paving blocks, the jointing and bedding material, and the base material. Among the findings, results showed that the shape of the paver could reduce the value of permanent deformations, with UNI-Anchorlock^® and UNI-Stone^® displaying the smallest permanent deformations.

CONCRETE SEGMENTAL PAVEMENTS AESTHETIC AND PERFORMANCE SOLUTIONS
Brian Shackel and A.R. Pearson - 1996
Proceedings, Fifth International Conference on Concrete Block Paving, Tel Aviv, Israel. This paper summarizes the historical development of concrete block paving to the present day in Australia. The advantages and ever-increasing applications of concrete paving block are discussed. They have been established as a viable alternative for heavy-duty pavements in areas such as hardstands, cargo-handling facilities, and container/port areas. Recent case histories are included. Industry revision of technical design and computer software also are discussed, as well as newly released industry product performance specifications and the new Australian Standards for concrete block pavement.

SELECTION OF A PAVEMENT SYSTEM FOR HEAVILY-LOADED MARINE TERMINAL
Ross McGillivray and Carl Fielland - 1995
Ports 95, American Society of Civil Engineers, New York, NY. This paper represents the decision process by which the pavement system and its components were selected for the upland cargo staging area at Berth 208, Port of Tampa. It concluded that a UNI-Anchorlock^® pavement system, supported on a geo-grid reinforced granular base course would provide the best solution to the design and construction requirements. See our Port of Tampa Case Study. Also available - Life-Cycle Cost Analysis Data from the Port of Tampa - This is only available in print form. Click here to order.

NASA CONCRETE PAVER EVALUATION
UNI REPORT - 1994
In addition to the Yager report (see NASA Friction Evaluation of Concrete Pavers to follow), this paper included results of ALDF Test Runs on a variety of paver block sections and color photographs. UNI-Anchorlock^® was the only paver to show no deformation under these tests. For copies of this testing, please click here to order. (Available only as a print version.)

NASA FRICTION EVALUATION OF CONCRETE PAVERS
Thomas J. Yager - 1993
Proceedings, BIBM'93 International Congress of the Precast Industry, Washington, DC. The development and use of concrete paving blocks is reviewed and some general specifications for application of this type of pavement surface at airport facilities are given. Two different shapes of interlocking concrete paving blocks installed in the track surface at NASA's Langley Aircraft Landing Dynamics Facility are described. Both wet and dry surface conditions were evaluated on the two concrete paver surfaces and a conventional, non-grooved Portland Cement concrete surface.

USE OF UNI-COLOC (ANCHORLOCK)FOR INDUSTRIAL PAVEMENT
John Knapton - 1988
Research report demonstrates how the British Port Association Heavy Duty Pavement Design Method can be applied to UNI-Anchorlock^® to produce pavements that take into full account the enhanced performance of this product. The report shows that by substituting UNI-Anchorlock^® for conventional rectangular concrete pavers, the serviceable life of the pavement can be doubled. Tables are included showing thicknesses required for the base of industrial pavements with various types of soils and levels of pavement usage.

We have many additional reports and articles that may be of interest to the design professional. Click here to inquire about your area of interest, or to order any of the research listed above.