Verifi Concrete Quality Blog

Posts Tagged ‘slump’

Case Study: In-Transit Superplasticizer for Faster Concrete Pumping

by Verifi

Ozinga Ready Mix Concrete used Verifi® to ensure consistent slump and accelerate concrete pumping on a 9-story apartment building in downtown Chicago.

The tight space on the project site meant that the contractor, II in One Contractors, Inc. of Chicago, needed every load to arrive at the right slump, ready for concrete pumping.  This would normally be a challenge because of downtown traffic delays causing variable transit times and differences in slump loss.

Ozinga’s Quality Control department instructed Verifi software to make automatic superplasticizer additions in transit to achieve and maintain the ordered slump. This resulted in a 66% improvement in discharge slump vs. ordered slump and a 10% reduction in the time the trucks spent on site. The use of superplasticizer to change the slump ensured that critical concrete properties like setting, strength, and durability were not negatively affected.

“There were fewer delays without concrete at the pump when Verifi was used” according to Robert McGee, President of II in One Contractors.  “I would like to use Verifi on every pour.”

Read the full Lake Street Case Study here.

Superplasticizer Slump Concrete Pumping

VERIFI® DELIVERY REPORT

Verifi Feature: Ticketed Slump Override

by Verifi

Is it OK for the slump of the concrete to not match the slump on the batch ticket?

Yes…in some cases.

For example, on a pumped job, the ticket may indicate the slump at the point of placement; that is, the end of the pump line. Due to slump loss during pumping, the concrete should be discharged from the truck at a slump greater than shown on the ticket.  In this example, Verifi would need to manage the slump to a target greater than the ticketed slump.

In another example, the contractor orders one slump but after the first load quickly realizes he needs a higher slump.  The concrete producer needs to override the slump on loads that are already ticketed so Verifi can start managing to the higher slump target.

Verifi can accommodate these cases with the Ticketed Slump Override feature. With this feature, the concrete producer enters the order number, date, location, mix code, and new slump for the override. Verifi will then use the new target slump, even if different from what is shown on the ticket. Verifi typically receives the ticketed slump through an interface with the batch plant software.

concrete slump ticket

A new override has to be entered each day, as job conditions affecting the override can change daily. The override can be turned on or off at any time.

Verifi keeps a record of all ticketed slump overrides. Access can be restricted to Verifi users with authority to change the slump.

ticketed slump override

The Ticketed Slump Override feature enables Verifi to adjust to the new slump in transit, which helps save time at the jobsite and avoids imprecise manual adjustments of slump.

Verifi customers can contact their Business Analyst to get started using the Ticketed Slump Override.

Load of the Week | Water & Superplasticizer in Transit

by Verifi

In today’s Load of the Week, Verifi automatically added both water and superplasticizer to reach the contractor’s desired slump.

Here’s what transpired:

1) The concrete was batched below the target initial slump of 5 inches.

2) Verifi automatically added water up to the maximum allowed for the load, then switched to superplasticizer to reach the target slump. This ensured the maximum water/cement ratio was not exceeded and the design concrete strength and durability were not compromised.

3) The target slump was changed from 5 to 8 inches. This was done at the request of the contractor. Verifi enables concrete producers to change the slump target at the request of the contractor, provided the change is within the design parameters of the mix. Note that the change was requested before the truck arrived on site. Therefore, the concrete producer could override the target slump and Verifi could adjust slump to the new target before the truck arrived on site.

4) Verifi continued to add superplasticizer to reach and maintain the new target slump of 8 inches.  All additions were automatic and did not require driver input.

5) The contractor poured the concrete shortly after arrival.

 

Concrete Superplasticizer

 [LP = leave plant, AS = arrive site, BP = begin pour, LS = leave site, RP = return plant]

Nominate a future Load of the Week by emailing the ticket number and ready mix concrete supplier name to feedback@verificoncrete.com.

Load of the Week | Automatic Superplasticizer

by Verifi

In today’s Load of the Week, Verifi adjusted the slump of the concrete by making automatic superplasticizer additions.

Verifi made three automatic superplasticizer additions to adjust the slump from 4 inches after batching to the 8-inch target. Instead of one large addition, Verifi’s unique algorithm monitored the superplasticizer performance in this particular load and precisely adjusted the three additions to reach but not exceed the target slump. Verifi used the time from batching to arrival on site to make this slump adjustment so that the concrete was ready to pour upon arrival, even though the contractor was not ready.

 

automatic superplasticizer

[LP = leave plant, AS = arrive site, BP = begin pour, LS = leave site, RP = return plant]

Nominate a future Load of the Week by emailing the ticket number and ready mix concrete supplier name to feedback@verificoncrete.com.

Load of the Week | Superplasticizer in Transit

by Verifi

In today’s Load of the Week, Verifi added superplasticizer in transit to achieve the target concrete slump. Verifi made three additions of a polycarboxylate-based superplasticizer  to increase the slump of the concrete. The use of multiple, small superplasticizer additions enables the slump to be targeted more precisely than with one large addition.

In most cases, some of the water is withheld (or “trimmed“) during batching so that it can be added after batching: at the plant, in transit or at the site. In the case of the Load of the Week, all water was added during batching and no water was available to be added by Verifi. Instead, superplasticizer was withheld at batching so that it was available to be added after batching.

 

Superplasticizer in Transit

[LP = leave plant, AS = arrive site, BP = begin pour, LS = leave site, RP = return plant]

Nominate a future Load of the Week by emailing the ticket number and ready mix concrete supplier name to feedback@verificoncrete.com.

Load of the Week | Waiting to Pour Concrete

by Verifi

Today’s Load of the Week arrived on site 25 minutes after batching.  The contractor initially discharged a small amount of concrete upon arrival.  After a 30-minute delay, the contractor began to pour the remaining concrete.

Verifi continued to manage the load during this delay by automatically adding water so that when it was time to pour concrete, the slump was on target.  The driver followed prompts from Verifi to mix at high speed after water additions, per specification.  In addition, Verifi accounted for the the smaller volume in the mixing drum after the initial discharge.  This was important in both accurately measuring slump and in recording the amount of water added in gallons per cubic yard.

Concrete Load of the Week

© Verifi LLC

[LP = leave plant, AS = arrive site, BP = begin pour, LS = leave site, RP = return plant]

Nominate a future Load of the Week by emailing the ticket number and ready mix concrete supplier name to feedback@verificoncrete.com.

Load of the Week | Concrete Slump on Target

by Verifi

We’ve previously discussed whether it’s best to batch above, below, or at the target concrete slump.

Without Verifi, many ready mix concrete producers find that it makes the most sense to batch above target slump.  With Verifi, however, it makes more sense to batch at or slightly below target.  This avoids the risk of delivering concrete above the target slump.  Verifi can add water automatically in transit to reach the target slump, which saves time at the plant and jobsite.

Today’s Load of the Week was batched below the target slump.  Verifi added water automatically to reach and maintain the target slump until discharge.  

 Load of the Week

© Verifi LLC

[LP = leave plant, AS = arrive site, BP = begin pour, LS = leave site, RP = return plant]

Nominate a future Load of the Week by emailing the ticket number and ready mix concrete supplier name to feedback@verificoncrete.com.

Load of the Week | Concrete Temperature Staying Warm

by Verifi

Today’s Load of the Week was delivered as extreme cold weather covered most of the US, including this delivery.

The initial temperature reading by Verifi, just as the concrete was entering the drum, was 32°F.  This temperature reflected the ambient conditions.  The temperature reading quickly jumped to 45°F, reflecting the addition of concrete in the mixing drum.  The temperature initially dropped due to the cold ambient conditions, but then rose later in the delivery due to heat of hydration.  The concrete temperature was 46°F at the time of discharge.  Concrete specifications typically set a minimum temperature of 40 to 50°F depending on the size of the pour.

Despite the cold temperature, Verifi made four automatic water additions to maintain slump until the concrete was discharged at an age of 33 minutes.

Concrete Temperature

© Verifi LLC

[LP = leave plant, AS = arrive site, BP = begin pour, LS = leave site, RP = return plant]

Nominate a future Load of the Week by emailing the ticket number and ready mix concrete supplier name to feedback@verificoncrete.com.