Investigation of Current and New Generation Cementitious and Supplementary Cementitious Materials for SCDOT Concrete

Portland cement-based concrete is widely used by the South Carolina Department of Transportation (SCDOT) in the construction of a vast array of transportation infrastructure such as pavements, bridges, culverts, retaining walls, etc., as well as in a number of precast concrete elements such as piles, pipes, girders, etc. Existing material specifications for the construction of these structures are based on approved concrete mixture proportions that use Ordinary Portland Cements (OPC) that meet AASHTO M 85 specifications in combination with or without Supplementary Cementitious Materials (SCM) such as fly ash, slag, and silica fume. In recent years, the Portland cement industry has taken an industry-wide action to reduce the carbon footprint of cement by transitioning from production of conventional OPC to Portland Limestone Cement (PLC). PLCs are designed to be a blend of Portland cement clinker with a maximum of up to 15% interground limestone, by mass of the cement (ASTM C595, AASHTO M240). Typically, PLCs have a higher fineness than OPC to match the performance requirements of traditional OPC in all regards. However, PLCs from different manufacturers may contain different levels of limestone content in their composition within the maximum limit of 15% by mass of cement. As a result, the performance of different PLCs may be slightly different from each other and the impact of these cements on the performance of concrete therefore could be different. Further, the interaction of PLCs with a range of chemical admixtures that are typically used in concrete to affect the slump, setting time, air entrainment, shrinkage, and other characteristics of concrete needs to be examined and any changes necessary to account for these differences in the mix design of structural grade concrete should be documented and accounted for. In addition to PLCs, a new generation of low-carbon cements such as calcium sulfoaluminate cements (CSA) and others have emerged, that may find a role in the construction of unique and niche transportation infrastructure elements. Currently, no SCDOT specifications exist to address cements such as CSA and others. Simultaneously, a range of new supplementary cementitious materials (SCMs) has become available in the marketplace (for ex: harvested ashes, ground glass pozzolans, calcined clays (such as metakaolin), natural pozzolans, etc.) as the availability of traditional SCMs such as fly ashes and slag has become uncertain. Also, new test methods to assess reactivity of SCMs, such as isothermal calorimetry based R3 test (ASTM C 1897-20), that are superior to traditional methods such as Strength Activity Index have become available, and these methods need to be adopted in the SCDOT standard specifications. The reactivity of the new generation of SCMs with the PLCs is not thoroughly established and needs to be investigated. In light of the aforementioned gaps in the knowledge and given that new materials and new methods have evolved since the last revision of the Standard Specifications, it is essential to investigate whether the existing concrete mix design methods and the structural grades of concrete approved in the 2007 Standard Specifications for Highway Construction per Table 701.2.12.2 can be achieved with the new generation of cementitious materials. In addition, it is important to examine whether any changes need to be made to the current concrete mix design procedures to realize any benefits from the new generation of cementitious materials, without compromising the quality of concrete for intended application.

Language

• English

Project

• Status: Active
• Sponsor Organizations:

  Clemson University

  110 Lowry Hall
  Box 340911
  Clemson, SC  United States  29634-0911
• Principal Investigators:

  Rangaraju, Prasad

• Start Date: 20240801
• Expected Completion Date: 20270731
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Admixtures; Cement; Concrete; Mix design; Specifications
• Identifier Terms: South Carolina Department of Transportation
• Subject Areas: Highways; Materials;

Filing Info

• Accession Number: 01953676
• Record Type: Research project
• Source Agency: South Carolina Department of Transportation
• Files: RIP, STATEDOT
• Created Date: Apr 28 2025 9:11AM