Calibrating the Iowa pore index with mercury intrusion porosimetry and petrography.

Details

• Creators:
  Hasiuk, Franciszek ; Firdaus, Muhammad ; Ridzuan, Ahmed ; Taylor, Peter
• Corporate Creators:
  Iowa State University. Institute for Transportation
• Corporate Contributors:
  Iowa. Dept. of Transportation ; United States. Federal Highway Administration ; Midwest Transportation Center ; United States. Department of Transportation. Office of the Assistant Secretary for Research and Technology
• Subject/TRT Terms:
  Coarse Aggregates Coarse Aggregate Helium-mercury Mercury Petrography Porosimeters Porosity
• Publication/ Report Number:
  InTrans Project 15-553
• Resource Type:
  Tech Report
• Geographical Coverage:
  Iowa;United States
• Corporate Publisher:
  Iowa. Dept. of Transportation
• Abstract:
  The Iowa Pore Index (IPI) test is a fast, non-destructive, inexpensive, and environmentally friendly test used by several
  
  Midwestern state departments of transportation to determine the volume ratio of macropores to micropores in a coarse rock
  
  aggregate. When combined with x-ray diffraction and x-ray fluorescence, this method has been shown to be effective in
  
  predicting the performance of aggregates in portland cement concrete. The test has the potential to replace mercury porosimetry
  
  and be integrated into any petrophysical laboratory.
  
  This research aimed to understand the geological factors (depositional environment, facies, grain and pore types, texture, and
  
  paragenesis) responsible for the results of the IPI test. Samples of various geologic ages were collected around Iowa to represent
  
  different combinations of accepted and rejected porosity and clay contents. The pore index of each sample was calibrated
  
  quantitatively via helium and mercury porosimetry and qualitatively via thin section petrography.
  
  The findings show that even the most homogeneous sources have at least three different rock types. Petrographic analysis showed
  
  that limestones with a sparite matrix, peloidal grains, and a low matrix-to-allochem ratio (i.e., grainy) are better for road
  
  construction than limestones with a micrite matrix, skeletal grains, and a high matrix-to-allochem ratio (i.e., muddy). Dolostones
  
  with fine to coarse grains, crystal-supported euhedral to subhedral rhombs, and porous intercrystalline areas are more desirable
  
  than dolostones with very fine grains and a tightly interlocking crystal mosaic in anhedral form.
  
  Several linear models were developed to relate IPI to helium porosity. Limestones with a helium porosity less than ~7% and
  
  dolostones with a helium porosity greater than ~13% were found to be desirable for use in road construction. The critical range of
  
  pore-throat size was found to be between 0.02 and 0.1 µm. Coarse aggregates with modal pore throat sizes above this range were
  
  found to be desirable for use in road construction
  
  
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:f270c0bbe19b0627f82e58ebed9086d85c70187afa9e087b3e98a7ebc54b1936c90dcfbcb10875bb634dbb617ea26de9f13d0a99da575bb5f57d6ad7dda8f0a5
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/32887/dot_32887_DS1.pdf
• File Type:
  [PDF - 3.11 MB ]