MnROAD | NRRA | Structure & Teams | Rigid Team
Reducing Embodied Carbon with Mineral-Blended Polymeric Microspheres
Status: In development
Objectives
This project will evaluate the performance of a mineral-blended polymeric microsphere powder used to construct concrete pavement test sections at MnROAD. The microsphere concrete mixtures will be compared with a reference mixture that contains conventional air entrainment and existing mixtures evaluated at MnROAD. Performance will be monitored over a 3-year period. The three-fold objectives for evaluating the microsphere mixtures are as follows:
- Determine the reductions in cement content that can be achieved with typical pavement concrete mixtures in which air-entraining agents are replaced with the microsphere-powder blend.
- Develop test data on strength and freeze-thaw durability for selected concrete mixtures to support application of the microsphere concrete mixtures in pavement construction.
- Quantify the sustainability benefits of use of microsphere concrete in lieu of conventional air-entrained concrete mixtures.
Laboratory testing on specimens cast during pavement construction will be performed to evaluate strength, modulus of elasticity, resistivity, and freeze-thaw durability. Field data collection will include surface distress surveys, falling weight deflectometer (FWD) testing, ride quality measurements, joint faulting and movement, embedded strain sensor data, ultrasonic tomography (MIRA) testing, curling and warping measurements, and examination of core samples. Results from this project will demonstrate the effectiveness of the mineral-blended polymeric microsphere powder to be used in concrete mixtures to support reductions in cementitious materials content while also supporting freeze-thaw durability. The feasibility of using mineral-blended polymeric microsphere powder in large-scale pavement applications will be evaluated, as well as the impact of use of this material to support both durability performance and reduced environmental impact of concrete. Findings of this work may also support use of mineral-blended polymeric microsphere powder in applications where supplementary cementitious material (SCM) characteristics may cause issues with conventional air entraining admixtures (e.g., higher carbon fly ash), thus allowing marginal SCMs to be more readily used in concrete. Other benefits of the microsphere-powder blend would include (i) eliminating the production and placement issues related to pumped air-entrained concrete; (ii) allowing for dense, polished, machine-troweled surfaces to be specified for concrete slabs in freeze-thaw environments; (iii) enabling concretes with a stiff consistency that are difficult to air entrain, such as pervious concrete and roller-compacted concrete, to be frost resistant; and (iv) eliminating the need to reject truckloads of concrete due to improper levels of air entrainment, thereby avoiding the use of more portland cement than necessary to complete a project.
It has suggested that the proposed test sections could be the top layer for the system being proposed by ARM. Details of how these can be combined into a single project can be negotiated when appropriate.
Tasks
Task 1: Literature review
A review of relevant literature will be performed. The search and review will focus on published literature, ongoing studies, recent industry presentations, and other available resources on freeze-thaw durability of concrete, assessment of field performance of concrete pavements, and approaches to quantify sustainability of concrete mixtures.
- Deliverable: The findings of the literature review will be compiled and included either in the final report or as a separate deliverable, as requested by the project technical advisory panel (TAP).
Task 2: Concrete mixture design development and testing
The research team will develop three highway concrete pavement mixture designs. Two will include mineral-blended polymeric microspheres and one will serve as a reference or control mixture. Mixtures will include materials used in the vicinity of MNROAD or similar to those materials. Mixtures anticipated to be developed are as follows.
- Control, conventionally air-entrained concrete mixture, typical MnDOT highway concrete
- Mixture with microspheres (no conventional air entrainment), same cementitious materials content and w/cm ratio as the control mixture (mixture 1).
- Mixture with microspheres (no conventional air entrainment) and reduced cement content (approximately 10 to 15% cement reduction is anticipated based on previous research) but approximately the same cementitious materials content as mixture 1. Same w/cm ratio and target strength as the control mixture (mixture 1).
Fresh concrete tests will be performed to obtain measurements of workability, temperature, air content (with pressure meter – ASTM C231), microsphere content (with volumetric meter, ASTM C173, but without use of isopropyl alcohol), and SAM number for the air-entrained concrete. Laboratory testing will be performed to evaluate compressive strength, modulus of elasticity, resistivity, and freeze-thaw durability. Strength, modulus, and resistivity tests will be performed at 3, 7, 28, 56, and 90 days.
- Deliverable: A memorandum providing final mixture designs and test data will be prepared and provided to the TAP.
Task 3: Construction preparation, construction, and testing
The research team will work with MnROAD personnel to support construction of test cells using the three mixtures developed in Task 2. The microspheres will be provided to the contractor by the supplier, along with detailed instructions on preparing microsphere concrete for placement. Support will be provided during test batching, if requested. The research team will also work with MnROAD personnel to support the implementation of sensors, as requested. Two research personnel will visit the site for one to two days to document the construction activities. Fresh and hardened concrete test specimens will be cast by MnROAD personnel during construction, and data will be collected by MNROAD personnel and provided to the research team for analysis. Fresh concrete tests will be performed to obtain measurements of workability, temperature, air content, microsphere content, and SAM number. Laboratory testing will be performed to evaluate compressive strength, modulus of elasticity, resistivity, and freeze-thaw durability. Strength, modulus, and resistivity tests will be performed at 3, 7, 28, 56, and 90 days. The performance of the two microsphere concrete mixtures will be compared to the performance of the conventionally air-entrained concrete mixture. An evaluation of the impact of the use of microspheres and reduced cement content on laboratory-measured fresh/hardened properties and durability performance, will be determined.
- Deliverable: A memorandum providing a summary of the construction process, test results, and analysis will be prepared and provided to the TAP.
Task 4: Performance evaluation
Performance data collected by MNROAD personnel will be provided to the research team at the end of years 1, 2, and 3. This data is anticipated to include distress survey information, FWD data, ride quality measurements (seasonal), data collected from embedded sensors, MIRA and fault meter measurements, joint opening measurements, curling and warping measurements, and data collected from cores. Data on traffic, deicing activities, and other supporting information (if available) will also be provided to the research team. The research team may also be provided with performance data for other test cells of interest to facilitate comparisons, as deemed appropriate by the project team, MnROAD, and the TAP. Using this information, the research team will compare the performance of the pavements constructed with the two microsphere concrete mixtures to that of the control, conventionally air-entrained concrete mixture. An evaluation of the impact of the use of microspheres on the performance of the pavement, as well as the impact of the reduced cement content, will be determined.
- Deliverable: A memorandum providing a summary of evaluation will be prepared at the end of each year and provided to the TAP (year 1, year 2, and year 3).
Task 5: Sustainability evaluation
Environmental data on materials used to construct these test cells will be collected prior to, or shortly after construction. An assessment of the environmental impacts of each mixture included in this project will be performed using approaches promoted by FHWA and supported by the TAP. It is anticipated that environmental impacts of most materials used in construction of MnROAD will have publicly available environmental product declarations (EPDs) or other environmental data published by the producers. Indicators to be included in the evaluation can include global warming potential, ozone depletion potential, and others as indicated by the TAP. Using this data, a lifecycle assessment (LCA) will be performed using FHWA’s Pavement LCA Tool. The environmental impacts of the three test cells constructed as part of this work will be compared to one another, as well as to the impacts of other cells of interest to MNROAD and the TAP. It is anticipated that the results of the environmental impacts of the microsphere test cells could be compared to those of the ongoing MnROAD field demonstration of alternative materials for concrete, which also focuses on assessing the constructability, performance, and sustainability of concrete pavement mixtures with novel materials and low-carbon mixture design/proportioning approaches.
- Deliverable: A memorandum providing the sustainability evaluation in draft format will be prepared in year 3 and provided to the TAP. TAP feedback will be solicited and incorporated into a revised version of the evaluation, to be presented in the project final report.
Task 6: Draft/final report and technical brief
The research team will prepare a final report, which will be submitted to the TAP in draft form for review prior to finalization. It is anticipated that the final report will contain the following sections/content:
- Introduction
- Literature review summary
- Concrete Mixture Design Development
- Pre-Construction and Construction
- Laboratory Test Results
- Performance Evaluation
- Sustainability Evaluation
- Conclusions and Recommendations
- Appendices – full literature review, laboratory data, field data, sustainability evaluation data, other relevant information as appropriate.
- Deliverable: A draft final report provided to the TAP for review three months prior to the end date of the project. A final report that has been revised to include/address TAP feedback will be provided by the project end date
Project team
Email the Project Team
Principal Investigator: Peter Taylor, Ph.D., Iowa State University, ptaylor@iastate.edu
Technical Liaison: Jacob Gave, MnDOT, jacob.gave@state.mn.us
Technical Advisory Panel (TAP): Contact us to join this TAP
- Emil Bautista, MnDOT
- Tom Burnham, MnDOT
- Dan Gancarz, Illinois Tollway
- Jacob Gave, MnDOT (TL)
- James Krstulovich, Illinois DOT
- David Lim, Caltrans
- Tirupan Mandal, WisDOT
- Carlos Moro, Texas State University
- T.J. Murphy, NDDOT
- Joseph Podolsky, Minnesota DOT
- Brett Trautman, Missouri DOT
- Xijun (Jeff) Shi, Texas State University
Related materials
- Initial Project proposal (PDF), 5/5/2023