We're a small but mighty team of concrete consultants.

At Minnesota-based Beton Consulting Engineers, LLC, we approach concrete from chemical, materials, and structural engineering perspectives and have worked on projects all over the world.

How the Beton team works

Our team members have diverse viewpoints, knowledge and skill sets that we often combine to solve client problems. We believe our collaborative approach results in unique, productive solutions. As our client, you’ll receive thoughtful, fresh ideas based on science, intuition and years of experience. We welcome your thoughts and experience into our brainstorming process, too. Combined, our team members lead and serve on 25 American Concrete Institute (ACI) committees and subcommittees. ACI is the leading authority and resource for developing concrete specification standards. Also, we are LEED accredited as well as professionally licensed in 15 states. Let us analyze, diagnose, explain, predict, and design your concrete.

Photo of engineer and owner Kevin MacDonald | Beton Consulting Engineers

Kevin MacDonald, President and Principal Engineer

PE in Minnesota, and Florida and P.Eng. in Ontario, British Columbia, and Alberta, Canada.

Kevin is Beton’s founder and president. He is a Fellow of the American Concrete Institute (ACI) and a member of ASTM, ASCE, the Concrete Society and Professional Engineers Ontario.

His commitment to ACI includes a role as the past chair of the 132-Responsibility in Concrete Construction and chair of of subcommittee 130-0B Production/Transport/Construction and 302 Construction of Concrete Floors. Further, he is a member of ACI committees 211-Proportioning Concrete Mixtures, 212-Chemical Admixtures, 223-Shrinkage-Compensating Concrete, and 232-Fly Ash in Concrete and 318 sub A.

In addition to his concrete consulting work, Kevin is an assistant professor at the University of Wisconsin-Stout in the construction management program where he teaches courses in concrete, reinforced concrete design and heavy construction. He brings considerable experience in field and lab concrete, quality control and problem-solving to his students and clients.

He earned a B.S. in Chemical Engineering as well as a Master’s and PhD in Engineering Materials from the University of Windsor in Ontario. Quality of concrete remains one of Kevin’s interests. He is heavily involved in ACI certification with the Aggregate and Ready Mixed Concrete Association of Minnesota.

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Rachel Detwiler, Principal Engineer

P.E. in Arizona, Connecticut, Illinois, Indiana, Iowa, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Jersey, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Washington, and Wisconsin.

Rachel is a civil engineer and a fellow of the American Concrete Institute. She teaches technical writing at the University of St. Thomas in St. Paul, MN, and writes most of the  blog posts for our website. With more than 35 years’ experience, she is an expert in concrete testing, construction troubleshooting, and failure analysis.

Rachel designed and directed a multi-laboratory test program that became the basis for changing the relevant ASTM standards to allow 4 inch x 8 inch cylinders to be used on an equal basis with 6 inch x 12 inch cylinders for concrete acceptance testing. She has investigated numerous construction defects and concrete failures, developing practical solutions for her clients. She has also served as an expert witness in concrete-related lawsuits.

Rachel is a member of ACI committees 201-Durability of Concrete, 214-Evaluation of Results of Tests Used to Determine the Strength of Concrete, and 234-Silica Fume in Concrete.

Rachel holds a B.S. in Civil Engineering, an M.S. in Structural Engineering, and a PhD in Civil Engineering Materials from the University of California at Berkeley. She was also a postdoctoral fellow at Institute for Building Materials at the Norwegian University of Science and Technology in Trondheim, Norway.

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Photo of petrographer Mark Lukkarila | Beton Consulting Engineers

Mark Lukkarila, Principal Petrographer and Materials Scientist

B.A. in Earth Science

Mark has technical expertise in the cement, concrete, masonry, and aggregate industries. He is a fellow of the American Concrete Institute and has extensive knowledge of cementitious systems, cement and hydration chemistry, gained over more than 30 years of experience. He has performed petrographic examinations of concrete, aggregates, and masonry as well as petrographic examination of historic mortars and concrete. He also has extensive experience with mixture proportioning of shotcrete dry pre-blended mixes.

Mark’s gone out to big projects like the Beacon Hill tunnel in Seattle, and the San Vicente Tunnel in San Diego for troubleshooting and has worked as a research laboratory manager and technical services director in the cement industry, where he became adept at interpreting process conditions through the use of clinker microscopy techniques.

Mark also has extensive experience with new product development and troubleshooting product performance as well as process related issues. His participation in ACI includes: Chair of E701-Materials for Concrete Construction, 524-Plastering, and 225-Guide to Selection and Use of Hydraulic Cements. He is a voting member of 221-Aggregates, 240-Pozzolans, 506-Shotcreting, C621-Cement Tester Certification, and E710-ACI University Programs.

Mark also is active in ASTM and is past-chair of subcommittee C09.46 on shotcrete, and is task group chair for C294 and C295; both relate to concrete aggregates. He’s an examiner and educator for ACI’s shotcrete nozzleman certification program. Mark received a B.A. in Earth Science from the University of Minnesota Duluth.

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Photo of scientist Julie Buffenbarger | Beton Consulting Engineers

Julie Buffenbarger, Senior Scientist and Sustainability Principal


Julie is a Fellow of the American Concrete Institute (ACI). She is the chair of 130-Sustainability of Concrete, and a member of 232-Fly Ash in Concrete, 132-Responsibility in Concrete Construction, and 234-Silica Fume in Concrete. She has more than 25 years’ experience in the concrete industry, including 10 years doing product development with a large, international admixture company and 12 years troubleshooting for a cementitious materials, concrete, and aggregate manufacturer.

Julie has promoted sustainable materials and construction practices with designers, contractors, and agency officials. She actively promotes the use of concrete products in building, road and energy markets. Julie’s expertise is in sustainability (LCA, LCC, and EPDs) and innovative implementation of sustainable and resilient construction practices; admixture chemistry, cementitious materials, concrete product development, troubleshooting concrete product performance, and concrete durability modeling and testing. She is proficient in multiple building and infrastructure sustainable rating systems. She earned a B.S. in Chemistry and M.S. in Organic Chemistry from Bowling Green State University, Bowling Green, Ohio.

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Image of junior engineer Sara Shuga | Beton Consulting Engineers

Sara Shuga, Senior Engineer

B.S. in Civil Engineering

Sara started working at Beton in 2020. She produces thermal control plans for mass concrete, develops concrete mix designs, conducts performance concrete R&D, and analyzes industrial slab designs.

She received her B.S. in Civil Engineering from Michigan Technological University and began her career as a civil design engineer in Chicago and the Twin Cities prior to moving to Denver, CO, where she was a Development Review Engineer for Jefferson County. Upon her return to the Twin Cities, she taught math and was the Environmental Health and Safety Coordinator at a private university. In 2014, she joined a ready-mix company as a materials engineer where she reviewed project specifications, designed concrete mixtures, and analyzed data in order to improve quality and service.

Email her sshuga@betonconsultingeng.com.

Lori MacDonald's photo | Beton Consulting Engineers

Lori MacDonald

Office manager

Lori has a background in banking, education, and organizational management. She is Beton’s primary contact for payroll, accounting, human resources, procurement, professional liability insurance and general inquiries.

Email her at betonadmin@betonconsultingeng.com.

Photo credits: Nick Lents, Lents Photography
Renee McGivern, Spark Plug Consulting