TR-808: A Sustainable Air-Entraining and Internal Curing Agent

Details

• Creators:
  Yellavajjala, Ravi Kiran ; Jalal, Asif
• Corporate Creators:
  North Dakota State University. Department of Civil and Environmental Engineering ; Arizona State University. School of Sustainable Engineering and the Built Environment
• Corporate Contributors:
  Iowa. Department of Transportation ; Iowa Highway Research Board
• Subject/TRT Terms:
  Admixtures Air Entraining Agents Compaction Concrete Pavements Curing Agents Freeze Thaw Durability Paving Porosity Shrinkage
• Publication/ Report Number:
  IHRB Project TR-808
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final Report: 6/1/2022-2/27/2025
• Corporate Publisher:
  Iowa Department of Transportation
• Abstract:
  Air entrainment of concrete is crucial to dissipate the tensile stresses introduced by the volume expansion of frozen water in the capillary pores of the concrete. The air void system achieved using popular surfactants is sensitive to the properties of cementitious materials, water content, admixtures, aggregate, etc. Furthermore, vibration, compaction, and mechanical paving can lower the efficiency of surfactants. Every 1% increase in the air volume reduces strength by 5% which could be partially compensated by higher binder content. Achieving a stable air void system without compromising the strength of concrete is the goal of this study. A bio-based hydrogel synthesized from cornstarch was investigated alongside commercially available superabsorbent polymers (SAPs) and air-entraining agents. Firstly, hydrogels and SAPs were embedded in cement mortar, and their performance was assessed through hydration enhancement, void structure development, and durability improvements. The internal curing ability of hydrogels was quantified using a hydrogel capsule method, revealing cyclic water release governed by humidity gradients. Additionally, microcomputed tomography (micro-CT) scanning demonstrated that cornstarch hydrogels at 3% mixing water content produced a robust void structure with high porosity and small voids, without significant strength reduction. The influence of hydrogels on F-T resistance was evaluated through compression strength, mass change, scaling resistance, and chloride penetration after prolonged exposure to brine solution. While traditional air-entraining agents provided superior F-T resistance by creating small, uniformly distributed voids, they also reduced strength. Conversely, SAPs and cornstarch hydrogels improved hydration and strength retention while offering moderate scaling resistance. The microstructural analysis confirmed that bio-based hydrogels enhance both internal curing and durability, positioning them as sustainable alternatives to conventional admixtures. Overall, this research highlights the potential of bio-based hydrogels for enhancing hydration, mitigating shrinkage, and improving cementitious matrix durability under harsh environmental conditions.
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:8d6d8c85e3237162d231ccaaf010d7c7b42098e8aa4ec5847458ec8985399c8066961cca655ce5bc8308c0196232eabd4c7d34d7c23133c95c81d25e2c792555
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/87528/dot_87528_DS1.pdf
• File Type:
  [PDF - 5.45 MB ]