Concrete with steel furnace slag and fractionated reclaimed asphalt pavement.

Details

• Creators:
  Brand, Alexander S. ; Roesler, Jeffery R.
• Corporate Creators:
  Illinois Center for Transportation
• Corporate Contributors:
  Illinois State Toll Highway Authority
• Subject/TRT Terms:
  • Slag
  • Reclaimed asphalt pavements
  • Calcium oxide
  • Concrete
  • Expansion
  • Shrinkage
  • Freeze thaw durability
  • Fracture properties
  • Modulus of elasticity
  • Coarse aggregates
• Publication/ Report Number:
  ICT-14-015 ; UILU-ENG-2014-2015
• Resource Type:
  Tech Report
• Geographical Coverage:
  Illinois
• Corporate Publisher:
  Illinois Center for Transportation
• Abstract:
  Steel furnace slag (SFS) is an industrial by-product material that can contain free calcium oxide (CaO) and free magnesium oxide (MgO), both ; of which can cause significant expansion when hydrated. SFS aggregates are therefore not commonly used in concrete, although SFS ; aggregates have been used as a high quality frictional aggregate for hot-mix asphalt (HMA) surface courses. The resultant fractionated reclaimed ; asphalt pavement (FRAP) when the HMA with SFS is removed has also seen little usage. ; This study aims to continue the previous work by the authors that indicated that up to 50% dolomite FRAP can be used in concrete as a ; replacement of coarse aggregate. The objective of this work was to evaluate the effects of SFS FRAP at 20% and 50% replacements of the ; coarse aggregate in concrete. In addition, the chemical, mineralogical, physical, and expansive properties of three SFS FRAP sources were ; investigated along with investigations of three virgin SFS sources for comparison. ; The chemical, mineralogical, and physical properties of the SFS FRAP and virgin SFS sources were similar to values presented in the literature. ; The estimated total free CaO content of the virgin SFS sources ranged from low (<0.1%) to high (3.4%), while the free CaO content of the SFS ; FRAP sources was estimated to be 1.0% to 1.5%. The free MgO content of the virgin SFS sources ranged from 0.2% to 2.2%. Autoclave ; expansion tests correlated well for the virgin SFS sources with regard to the free CaO content (i.e., high free CaO content resulted in high ; expansion), while the SFS FRAP with asphalt binder removed did expand, but not necessarily proportionally to the free CaO content. Autoclave ; expansion tests of the SFS FRAP with the asphalt binder resulted in contraction rather than expansion. The results validated the findings from ; other studies that have shown that SFS FRAP will not significantly expand because of the asphalt coating. ; Concrete tests revealed that the strength, modulus, shrinkage, and fracture properties were similar between concretes with SFS FRAP and with ; dolomite FRAP. The modulus of elasticity was slightly higher for concrete with SFS FRAP compared with dolomite FRAP, possibly because of the ; presence of the stiffer SFS aggregate. The fracture properties were statistically similar for concrete with and without SFS FRAP aggregates. The ; freeze/thaw durability was reduced with higher SFS FRAP contents, possibly because of the asphalt coating on the FRAP rather than the SFS in ; the FRAP, because the mixes with 100% virgin SFS exhibited superior freeze/thaw durability. ; Based on these findings, it is evident that SFS FRAP can retain free CaO and free MgO contents, despite years in service in a pavement layer ; and/or years being weathered in a stockpile. The presence of the asphalt coating hinders, but may not necessarily prevent, the hydration of the ; free CaO and free MgO in the SFS. Therefore, it is recommended that the SFS FRAP be tested for free CaO, free MgO, and asphalt contents and ; autoclave expansion potential prior to being utilized in a structural concrete layer. Immediate usage of SFS FRAP may not be detrimental for nonstructural ; applications, such as temporary roads or shoulders. To ensure that future SFS FRAP can be used in concrete pavements, the SFS that ; is presently used in HMA should be weathered and have low free CaO contents and low expansion potential.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/27893/dot_27893_DS1.pdf
• File Type:
  [PDF - 6.02 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:5448a21aa711db750a64531770051ac49fccf9d5d2382cbe81eb436cb96cdb96