Effectiveness of Magnesium-Alumino-Liquid Phosphate-Based Concrete as a Repair Material

Details

• Creators:
  Darwin, David ; O’Reilly, Matthew ; Salavati-Khoshghalb, Mohsen
• Corporate Creators:
  University of Kansas Center for Research, Inc.
• Corporate Contributors:
  Oklahoma. Department of Transportation. Office of Research and Implementation
• Subject/TRT Terms:
  Aluminum Concrete Aggregates Corrosion Cracking Evaluation Field Tests Freeze Thaw Durability Freeze Thaw Tests Magnesium Magnesium-alumino-liquid-phosphate (MALP) Concrete Magnesium-potassium-phosphate (MKP) Phosphorus Protection Rapid-setting Concrete Reinforced Concrete Repairing Shrinkage

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• Publication/ Report Number:
  FHWA-OK-26-01 ; 170
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Edition:
  Final Report: Jan 2023 - Oct 2025
• Corporate Publisher:
  Oklahoma. Department of Transportation
• Abstract:
  A proprietary magnesium-alumino-liquid-phosphate (MALP) concrete, manufactured by Phoscrete Corporation, is a rapid-setting repair material promoted for its ability to bond with portland cement concrete and protect reinforcing steel against corrosion. A related product, magnesium-potassium-phosphate (MKP) concrete, offers slower setting for easier placement, while MKP-VO combines MKP with MALP for vertical or overhead applications. This study evaluates the durability and protective performance of MALP (with and without the organic additive Endure), MKP, and MKP-VO under aggressive conditions relevant to reinforced concrete infrastructure. The study includes more than 120 corrosion specimens, 39 freeze–thaw specimens, 24 scaling specimens, and 39 shrinkage specimens to assess: (1) corrosion protection provided to reinforcing steel in cracked and uncracked concrete, including cases with pre-corroded reinforcement; (2) resistance to freeze–thaw cycling; (3) resistance to scaling under freezing and thawing with deicing salts; and (4) shrinkage behavior. Specimens in which MALP completely enclosed the reinforcing steel exhibited excellent corrosion performance. Specimens combining MALP with conventional concrete showed very low macrocell corrosion rates, but cracked specimens exhibited high total (macrocell plus microcell) corrosion rates. Field test specimens with MALP repair regions provided poorer corrosion performance than similar specimens cast with good quality conventional concrete, suggesting that the presence of cracks at the interface of repair regions permit water, oxygen, and deicing chemicals to reach the reinforcing steel. MKP did not provide good corrosion protection. MALP showed excellent freeze-thaw durability, while MKP failed quickly and MKP-VO performed moderately well but degraded over time. In the scaling test, MALP did not perform well while MKP and MKP-VO showed excellent scaling resistance. MALP and MKP-VO shrink while MKP exhibits initial expansion followed by shrinkage at a slower rate than MALP and maintains a net expansion.
• Format:
  PDF
• Funding:
  2317
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:1f2c56c28e293069564629bb83270628268ec54af635ab7e47083d17167c6fd8f034b5a93ddd15c668459258623bb2290281dcd8e5926178e13584d78a0be0c6
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/88886/dot_88886_DS1.pdf
• File Type:
  [PDF - 3.49 MB ]