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Compressive Strenght of Temporary Barrier

Question
State WI
Description Text

What is the spec. compressive strength for the temporary barrier that MwRSF developed for the pooled fund?

What was the design compressive strength for the temporary barrier that MwRSF developed for the barrier?

Keywords
  • Temporary Barriers
Other Keywords concrete, PSI
Date September 7, 2016


Response
Response The original NCHRP Report 350 testing of the F-shape barrier used by the Midwest Pooled Fund states specified a minimum concrete strength of 4,500 psi. 

Over time the original design has evolved somewhat. The current barrier system has been tested to NCHRP MASH in several different configurations including free-standing and reduced deflection applications. For the more recent testing the minimum concrete strength was specified as 5,000 psi.

Based on this, we would recommend the use of 5,000 psi concrete with the F-shape PCB in order to be compliant with the most recent testing.
Date September 8, 2016


Response
Response

What was the designed breaking strength of the barrier.

 

A lot of the concrete we spec. has a 28 day breaking strength between 4,000 and 4,500 PSI.   ASTM C825-06 indicates a 28 day design strength of 4,000 PSI for precast barrier.  Is this difference  in 28-day breaking strength significant?

 

Date September 8, 2016


Response
Response

Slightly lower compressive strength should not have a drastic effect on barrier capacity. Most of the impact damage we see is flexural cracking of the barrier due to the impact loads. We would not expect the flexural cracking or the moment capacity of the section to change much due to the compressive strength reduction as it is largely controlled by the reinforcing steel.

 

The reduced concrete strength will cause increased spalling, damage at the joints, and disengagement of the barrier toes. Shear capacity would be reduced as well. These effects may cause some additional issues with barrier performance, but that is difficult to quantify. 

Date September 9, 2016


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