Drop Weight Impact Test on Prepacked Aggregate Fibrous Concrete-An Experimental Study

Area of Science:

• Materials Science
• Civil Engineering
• Concrete Technology

Background:

• Prepacked Aggregate Fibrous Concrete (PAFC) is a popular composite material gaining global research interest.
• PAFC preparation involves creating a coarse aggregate skeleton within a mold, followed by grout filling and cement hydration.
• Standardized testing methods are crucial for understanding and optimizing PAFC properties.

Purpose of the Study:

• To investigate modifications to the ACI 544 drop weight impact test setup.
• To decrease the dispersion and improve the reliability of impact test results for PAFC.
• To evaluate the effectiveness of five proposed alterations in reducing result variability.

Main Methods:

• Experimental testing of 108 cylindrical PAFC specimens across 12 groups.
• Utilized steel and polypropylene fibers at a 2.4% dosage.
• Introduced five alterations: line impact (steel bar), notched specimens (line/cross), specialized loading plates (knife/line), and alternative bedding (sand/coarse aggregate).

Main Results:

• Line notched specimens combined with sand bedding significantly decreased the coefficient of variation (COV).
• Cross-line notched specimens and line impact with coarse aggregate bedding also effectively reduced COV.
• The modifications generally led to a more consistent set of test results.

Conclusions:

• The proposed alterations to the ACI 544 impact test setup are effective in reducing result dispersion for PAFC.
• Line impact, notched specimens, and specific bedding materials offer improved reliability in impact testing.
• These findings contribute to more consistent characterization of PAFC material behavior.