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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?

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?

System Performance Evaluation

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Portable Barriers

Applications

System Features

Date September 7, 2016
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Response
Response (active)	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.

Response

Response
(active)

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
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Response
Response (active)	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?

Response

Response
(active)

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
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Response
Response (active)	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.

Response

Response
(active)

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
Previous Views (126) Favorites (0)

Compressive Strenght of Temporary Barrier