ACI Foundation Research Projects

Nonlinear Wind Design of Steel Reinforced Concrete (SRC) Coupling Beams: Design Recommendations

Nonlinear Wind Design of Steel-Reinforced Concrete (SRC) Coupling Beams

Validation of Service Life Prediction for a 28-Year-Old Parking Garage Constructed of Low Permeability Concrete (Part 1)

Validation of Service Life Prediction for a 28-Year-Old Parking Garage Constructed of Low Permeability Concrete (Part 2)

A Collaborative Study to Determine the Critical Chloride Threshold Test, OCcrit, Variability due to Material Sources

Stress-Strain Analysis of Belite Calcium Sulfoaluminate Cement Concrete for Structural Applications

Benchmark Tests on Anchoring Columns to Foundations

Anchorage Pour-backs Durability

Chloride Desorption Isotherms of Cementitious Systems Exposed to Low-pH Environments

Development of FRP Retrofit Guidelines for Deficient Reinforced Concrete Horizontal Lateral Force Resisting Systems

Development of Large High-Strength Reinforcing Bars with Standard Hooks and Heads

Anchorage of High-Strength Reinforcing Bars in Concrete

Full-Scale Testing of a New Double-Beam Coupling Beam (DBCB) with a Simplistic Reinforcing Layout

Assessment of 2015 and 2018 E-Defense 10-Story Reinforced Concrete Buildings Based on ACI 318 and ASCE 7 Provisions

Axial Behavior and Transverse Reinforcement Requirements of UHPC Columns with Emerging Mixtures: Assessment of Existing ACI Provisions and New Developments

Determination of the Curing Efficiency of Externally and Internally Cured Concrete Using Neutron Radiography

Behavior and Design of Concrete Structures under Natural Fire

Effective Characterization of Recycled Concrete Aggregate (RCA) for Concrete Applications

Calibration of Simplified Creep and Shrinkage Models Developed Using Solidification Theory

Durability of GFRP Bars Extracted from Bridges with 15 to 20 Years of Service Life

Structural Response and Buckling Behavior of Slender Ultra-High Performance Concrete (UHPC) Columns

Towards Comparable Environmental Product Declarations of Concrete: Insights from a Meta-Analysis and Probabilistic Comparative LCA Approach

A Collaborative Study for the Development of a Standard Critical Chloride Threshold Test Method

Impact of Retarder-Induced Roughness on Shear Friction Capacity using Conventional and High-Strength Reinforcement

Shear Strength of Precast, Prestressed Steel Fiber Reinforced Concrete Hollow-Core Slabs

Recommendations for Unified Durability Guidance

Literature Review of Concrete Durability & Service Life Requirements in Global Codes and Standards

Development and Splice Lengths for High-Strength Reinforcement, Volume 1: General Bar Development

Development and Splice Lengths for High-Strength Reinforcement, Volume 2: Drift Capacity of Structural Walls with Lap Splices

Reinforced Concrete Coupling Beams with High-Strength Steel Bars

Acceptable Elongations and Low-Cycle Fatigue Performance for High-Strength Reinforcing Bars

Evaluating the Performance and Feasibility of Using Recovered Fly Ash and Fluidized Bed Combustion (FBC) Fly Ash as Concrete Pozzolan

Role of Microbial Induced Calcium Carbonate Precipitation on Corrosion Prevention

Guideline Development for Use of Recycled Concrete Aggregates in New Concrete

Prestandard for Performance-Based Wind Design

Low-Cycle Fatigue Effects on the Seismic Performance of Concrete Frame and Wall Systems with High Strength Reinforcing Steel

Ductile Reinforced Concrete Coupled Walls: FEMA P695 Study

Guidelines for Performance Based Seismic Design of Tall Buildings

Evaluation of Chloride Limits for Reinforced Concrete Phase A

Guide to Formed Concrete Surfaces

Setting Bar-Bending Requirements for High-Strength Steel Bars

High-Strength Steel Bars In Earthquake-Resistant T-Shaped Concrete Walls

Sustainable Concrete without Chloride Limits

Proposed Specification for Deformed Steel Bars with Controlled Ductile Properties for Concrete Reinforcement

Part 1 Materials: Defining Structurally Acceptable Properties of High-Strength Steel Bars through Material and Column Testing

Part 2 Columns: Defining Structurally Acceptable Properties of High-Strength Steel Bars through Material and Column Testing

Seismic Performance Characterization of Beams with High-Strength Reinforcement

Interface Shear Transfer of Lightweight Aggregate Concretes with Different Lightweight Aggregates

Serviceablility Behavior of Reinforced Concrete Discontinuity Regions

Evaluation of Seismic Behavior of Coupling Beams with Various Types of Steel Fiber-Reinforced Concrete

Brief Historical Overview of Yield Strength Determination in ACI 318

Determination of Yield Strength for Nonprestressed Steel Reinforcement

Reexamination of Punching Shear Strength and Deformation Capacity Corner Slab-Column Connection

Evaluation of Seismic Performance Factors and Pedestal Shear Strength in Elevated Water Storage Tanks

Mitigation of Steel Reinforcement Via Bioactive Agents

Modeling Parameters for the Nonlinear Seismic Analysis of Reinforced Concrete Columns Retrofitted Using FRP or Steel Jacketing

Improved Procedures for the Design of Slender Structural Concrete Columns

Assessing the Impact of Green Concrete Mixtures on Building Construction

Lab and Field Data for: Assessing the Impact of Green Concrete Mixtures on Building Construction

Transverse Reinforcement Requirements in Flexural Hinges of Large Beams of Special Moment Resisting Frames Subjected to Cyclic Loading - "Big Beam" Project

Development of Anchorage System for FRP Strengthening Applications using Integrated FRP Composite Anchors

Drift Capacity of Slab-Column Connections Reinforced with Headed Shear Studs and Subjected to Combined Gravity Load and Biaxial Lateral Displacements

Crack control and leakage criteria for concrete liquid containing structures

A Study of Static and Dynamic Modulus of Elasticity of Concrete

CLT and AE Methods of In-Situ Load Testing

Formwork Pressures for Self Consolidating Concrete

Assessing the Deicer Salt Scaling Resistance of Concrete Containing Supplementary Cementing Material

BIM Strategic Plan

2024 Funded Research

The ACI Foundation is committed to progress in the industry by funding needed research and will fund 8 research projects this year. Summaries of each project are below.

A Planning Study to Speed Up Broad Implementation of More Sustainable and Resilient Concrete Materials by the Pavement Sector

PI: Somayeh Nassiri, University of California - Davis
Co-PI: John Harvey, University of California - Davis
Endorsed by ACI Committee 240 - Pozzolans

This project will help break down institutional and governmental barriers to the development and implementation of natural pozzolanic resources which are abundant in North America. Naturally pozzolanic materials (both raw and calcined) will help reduce the carbon footprint of concrete by up to 50%. Furthermore, these same materials will increase the durability of concrete by 3x or more due to increased strength, decreased permeability, and mitigation of concrete maladies such as ASR and sulfate attack.

The primary deliverable of this project is a roadmap offering practical steps, including performance data and full scope for a pilot project, to surmount obstacles quickly. In response to environmental concerns regarding extensive global portland cement use, natural pozzolans have re-emerged as a sustainable replacement of a portion of portland cement in concrete. Additionally, natural pozzolans have long been acknowledged for enhancing the durability of concrete. Despite these advantages, the integration of natural pozzolans into mainstream practice has been slow, encountering numerous barriers. To tackle these challenges comprehensively, the project involves a thorough survey of stakeholders, including state and local government, ready mix concrete producers, and natural pozzolan suppliers, with the aid of industry associations and other organizations. The insights garnered from this survey will inform the development of a comprehensive roadmap featuring actionable steps to expedite the implementation of natural pozzolans in both minor and major concrete across the pavement sector. As an integral part of this roadmap, the project aims to widely publicize performance data gathered from extensive testing of a range of natural pozzolan concrete mixtures in an ongoing Caltrans project. This dissemination of information is strategically designed to enhance market acceptance and specification revisions. Furthermore, the project involves the full scope, budget, and partnership to construct and monitor a pilot demonstration project at the UC Pavement Research Center with natural pozzolan concrete mixtures in concert with the FHWA five-year cooperative agreement with UC Davis. Through these concerted efforts, the project envisions a significant acceleration in adopting natural pozzolans, promoting sustainability and resilience in the concrete pavement industry.

Examining the Abrasion and Carbonation Resistance of Portland Limestone Cement Systems for Industrial Floors

PI: Mehdi Khanzadeh Moradllo, Temple University
Endorsed by ACI Committee 225 – Hydraulic Cements

While many studies have been performed to compare the mechanical properties and permeability of PLC and OPC systems, there is a lack of research/experimental data on the abrasion resistance of PLC systems. In most cases, a fulfillment/distribution center has millions of square feet of concrete slabs that need to be durable for different types of traffic and millions of cycles. Therefore, further research is needed to systematically study the abrasion resistance of PLC systems using standard test methods. This project aims to address this need with the goal of providing the concrete industry with data to make informed decisions on the potential use of PLC systems for industrial floors. This study will examine the abrasion resistance of PLC and PLC+SCM systems, and the comparison with those of OPC systems according to ASTM C779-19, ASTM C944-19, and BS 8204-2. The objective of this study is to provide a fulfillment/distribution center with a cement system that is both durable and sustainable. This study will also examine the carbonation rate of PLC systems, and its impact on the abrasion resistance of concrete. Early-age carbonation of concrete could cause early delamination of concrete floors. The research findings will be prepared in the form of a technical note, webinar, and ACI journal publications. In addition, the outcomes of this research can be directly incorporated into ACI guidelines (e.g., ACI 225).

Three- Versus Four-Point Bending Test for The Identification of UHPFRC/FRC Tensile Constitutive Behavior

PI: Francesco Lo Monte, Politecnico di Milano
Co-PI: Barzin Mobasher, Arizona State University
Endorsed by ACI Committee 544 - Fiber Reinforced Concrete

This project aims at defining an experimentally-based procedure for the characterization of the stress-strain constitutive law in tension for FRC and UHPFRC, based on bending testing and analytical inverse analysis, with special attention to SLS strain range. This will be pursued via a combination of experimental testing, numerical analyses, and implementation of machine learning algorithms, devoted to a systematic comparison between 3- and 4-Point Bending Test (according to EN and ASTM standards). The clear definition of a robust method for assessing the stress-strain law in tension starting from the actual standardized bending tests is expected to further push forward the use of FRC and UHPFRC, with the final goal of including the developed method within the design guidelines of TC 544 and TC 239.

Leveraging Transfer Learning to Predict the Performance of Novel Concrete Mix Designs in an Expeditious Manner

PI: Stephanie Paal, Texas A&M University
Endorsed by ACI Committee 135 - Machine Learning-Informed Construction and Design

Machine learning has revolutionized almost every domain it has touched, from lending money to security infrastructure to advanced manufacturing and open gameplay, such as chess. It is highly likely that with the influx of machine learning applications in the concrete community, this will also revolutionize the concrete industry through new solutions such as the one proposed in this project. A powerful machine learning technique, known as transfer learning (TL) has the potential to address two important issues for the concrete industry. The first is optimizing mix designs towards sustainability. With the rapid introduction of new materials for concrete production (e.g. Type IL), as well as poorer quality and consistent materials (e.g. sands), it is a challenge is to keep mix designs at their optimum with the available materials for a given producer. The second is that for typical ML/AI methods, enormous amounts of data are required - especially with respect to the number of test results our particular industry generates. Transfer Learning, which has shown great promise in other industries to basically learn from one data set, and apply the learnings to another data, which may be low in number of data points. This technology has great potential to both optimize current mixes towards sustainable mixes, and also speed up incorporation/adoption of new materials by quickly recommending mix designs. The outcome of this project will allow ACI Committee 135 to have a representative application of ML that is extremely useful to the broader concrete community. The result of this work will be an open-source dataset and model(s) for use by anyone interested in implementing these ML techniques for rapid, accurate performance assessment of newly generated mix designs. Additionally, a TechNote will be developed to guide the industry on the procedure for implementation of the technique, and this TechNote will be weaved into the Emerging Technology Report our committee is currently developing.

Ultra-High Performance Concrete Compressive Model in Flexural Compression Zone

PI: Yi Shao, McGill University
Endorsed by ACI Committee 239 - Ultra-High-Performance Concrete

This project will investigate the compressive behavior of UHPC in flexural compression zones and develop practical design guidance through eccentric compression testing of large-scale UHPC specimens. The design guidance will include a UHPC compressive material model and compressive stress block parameters for flexural design.

Impact: High spalling/crushing resistance has been observed in UHPC flexural members, including beams and columns. However, the UHPC stress-strain relationship at the softening stage remains unknown and validated compressive models for predicting the crushing point behavior of UHPC beams/columns are not available. The developed compressive model in this project will be a fundamental component of UHPC flexural design theory. Further, utilizing the high compressive strength and ductility of UHPC will allow us to design UHPC specimens with a high reinforcing ratio. For the same flexural load capacity (i.e., flexural tension steel area), adopting a high reinforcing ratio means a significant reduction in cross-section size and thus the material usage and environmental impacts. Therefore, this project will also contribute to developing sustainable concrete structures with thin UHPC elements.

Potential usage by ACI committee: The proposed project directly supports the ACI 239-0C (Structural Design on UHPC) committee’s ongoing efforts in developing UHPC structural design guidance. Currently, the ACI 239 Structural Guidance can only provide a compressive model that describes the pre-peak behavior of UHPC since the post-peak behavior remains unknown. This project will fill this important knowledge gap and provide a comprehensive compressive model for UHPC flexural design. An appropriate compressive model is critical for predicting the flexural load capacity and flexural ductility of UHPC flexural members.

Analysis And Design of Concrete Bridge Deck Overhang Using GFRP Bars

PI: Khaled Sennah, Toronto Metropolitan University
Endorsed by ACI Committee 440 - Fiber-Reinforced Polymer Reinforcement and ACI Committee 343 - Concrete Bridge Design

This project investigates the analysis and design of bridge deck slab overhang due to vehicle impact to concrete barriers. The first task in this project includes a parametric study using finite element modeling to determine the applied bending moment (M) and tensile force (T) on deck overhang for different barrier test levels, length, and flexural stiffness and for overhang length and flexural stiffness. Empirical M and T equations for deck overhang design will then be developed. Task 2 involves developing a simplified design procedure for concrete sections reinforced with glass fiber-reinforced polymer (GFRP) bars subjected to combined M and T. Experimental testing on concrete sections subjected to large- and small-eccentric tensile forces will be conducted to verify the proposed design methodology, which will also apply to the design of GFRP-reinforced liquid containment structures, silos, bins, and bunkers. The third task includes testing to collapse actual-size GFRP-reinforced concrete TL-5 and TL-4 barrier-deck overhang systems to provide research information that is unavailable for deck overhang. Design examples of concrete sections subject to combined M and T in deck overhang and other structures will be developed. Based on this research, a new section on deck and deck overhang analysis and design may be included in the expected updated version of the ACI 343R-95: Analysis and Design of Reinforced Concrete Bridge Structures. The developed design methodology for GFRP-reinforced concrete section subjected to M and T may be included in Section 22: Sectional Strength of the ACI 440.11-22: Building Code Requirements for Structural Concrete Reinforced with Glass Fiber-Reinforced Polymer Bars as well as in the ACI PRC-440.1-15:Guide for the Design and Construction of Structural Concrete Reinforced with Fiber-Reinforced Polymer Bars. The developed design examples may be included in Chapter 11 – Design Examples of this guide with application to liquid containment structures, silos, bins, and bunkers.

Experimental Investigation of Use of UHPC to Simplify Structural Detailing of Precast Shear Walls in Seismic RegionsI

PI: Sriram Aaleti, University of Alabama
Co-PI: Michael E. Kreger, University of Alabama
Endorsed by ACI Committee 550 - Precast Concrete Structures (Joint ACI-ASCE)

This research addresses the implications of recent modifications in the ACI 318-19 Code on precast shear walls, with a specific focus on special structural walls located in seismic regions. These code changes necessitate increased dimensions and weight, and detailing requirements, impacting both shipping costs and the overall competitiveness of precast concrete. To address these challenges, the proposed investigation delves into the application of Ultra-high-performance concrete (UHPC), recognized for its superior mechanical properties compared to traditional concrete. The primary goal is to simplify seismic structural detailing in precast special walls using UHPC without impacting their lateral load performance. This involves an integrated approach comprising theoretical analysis, finite element simulations, and experimental testing. The significance of this pursuit lies in the potential for cost savings, weight reduction, and heightened competitiveness of precast concrete against alternative materials. Supported by ACI Committee 550 and aligned with some of the ACI 239 – UHPC Committee efforts, this research holds the potential to guide updates to ACI Code 550.3 and 550.6 and potentially can contribute to modifications in the design provisions in ACI 318 and ACI 319. The research team is comprised of three faculty members with expertise in UHPC, seismic design, concrete structures, and code development. The tasks encompass a comprehensive literature review, finite element modeling, and experimental testing of UHPC shear walls. The experimental testing will include reverse cyclic testing of shear walls incorporating UHPC, including a benchmark specimen constructed with traditional concrete. The overarching objective of this research is to unlock the full potential of UHPC in precast shear walls, presenting a cost-effective and competitive solution in seismic regions. The anticipated outcomes are positioned to enhance industry knowledge, potentially shaping revisions to ACI codes, and establishing UHPC as a credible alternative for seismic-resistant precast concrete construction.

Strength Reduction Factor for Plain Concrete

PI: Andrzej Nowak, Auburn University
Endorsed by ACI Committee 380 – Structural Plain Concrete; ACI Committee 332 – Residential Concrete Work; and ACI Committee 348 – Structural Reliability & Safety

Plain concrete is used for various structural elements that contain no reinforcement or less reinforcement than specified by the American Concrete Institute (ACI) Building Code. There have been significant developments in the concrete industry and a continuous growing interest in structural plain concrete. However, no major changes were made to the relevant ACI 318 Code since 1989.

The current ACI 318 design provisions approximate the flexural strength of plain concrete from the compressive strength, even though concrete fails primarily in tension rather than in compression. Compression-based design appears to be conservative as large factors of safety were used to prevent failure; it also inhibits the wider use of structural plain concrete because of an increased cost in constructability. Hence, there is an urgent need to investigate the flexural performance of plain concrete for linear elastic design and update the ACI design provisions as they have a considerable impact on the construction of plain concrete components and structures.

The objectives of the project are to statistically evaluate parameters for plain concrete for various limit states including compression, tension, and shear, and to determine the associated strength reduction factors using a reliability-based calibration. The statistical parameters and reliability-based calibration for plain concrete can result in the development of higher-performance concrete and safer design of plain concrete components and structures, which will be beneficial to several ACI committees. Furthermore, those may affect the costs and improve the competitive position of concrete versus other materials.

All research, summaries, opinions, findings, conclusions, and recommendations expressed in research reports are those of the authors and do not necessarily reflect those of the ACI Foundation. Any mention of trade names or commercial products does not constitute their endorsement by either the ACI Foundation or other project sponsors.

Purdue University research project

Casting prestessed slender columns at Purdue University for the in-progress project, Improved Procedures for the Design of Slender Structural Concrete Columns. Photo credit to Ryan Jenkins and Robert Frosch.

Major Funder: Precast/Prestressed Concrete Institute

Minor Co-funders: ACI Foundation, Portland Cement Association, and Concrete Reinforcing Steel Institute

RFP Application Information