Can we talk about Concrete?

[Streetcar]

A poster or two has linked some fibers that if mixed to proper ratio appears to replace rebar. Interesting. Good to know and some new learning to start on it seems.
One thing to keep in mind. What kind / brand of fibers does your local concrete plant have in stock and provide or can obtain ? Do they meet the requirements......

fiber is for crack control in the concrete, it does not add to strength of concrete

 

[Redlands Okie]

Thats always been my understanding. Thus the issue with the links on post number 13. I will have to read up some. Perfectly willing to learn new things, but learned long ago that often times their not all they seem to be.

 

[Tractor Seabee]

fiber is for crack control in the concrete, it does not add to strength of concrete

That's right. Re-rbar also performs that function. Slab on-grade concrete is not considered "structural concrete" as the sub-grade provides the structure. Poor sub-grade you need structural concrete so it will support itself. Then imposed loads have to considered when designing the reinforcement system. There are a lot of inter relationships for crack control. Yes concrete cracks, key is to get it to crack where you want it too, not where it wants too; therefore, fiber is part of that inter relationship same as reinforcement. I have seen plenty of concrete slabs of all types crack all over due to one or more of those items being not done right or done wrong.

One common example is control joints: If they are cut the morning after placement of the concrete, to bad the cracks where they want to be are already there even if you can't see them. Wait a few days. That is why on large dollar projects they have Professional Quality Control and Assurance at all stages; from the raw ground to the end of the curing process. Small jobs like the OPs, he is the QC. It is not arduous to get good concrete, just takes attention to detail. I can show you many slabs done 30-20 years ago with no re-bar or wire mesh that have no visible creaks today. I did a driveway at one of my houses, 24' wide 60' long full 4"+ thick, 4,000# concrete dosed with fiber and 5% air entrainment. 30 days after placement parked my 40' motor home on it and drove a loaded ten yard gravel truck over it. I put my money into the sub-grade.

Read one or all of those books.

Ron

 

[tjkubota93]

That's right. Re-rbar also performs that function. Slab on-grade concrete is not considered "structural concrete" as the sub-grade provides the structure. Poor sub-grade you need structural concrete so it will support itself. Then imposed loads have to considered when designing the reinforcement system. There are a lot of inter relationships for crack control. Yes concrete cracks, key is to get it to crack where you want it too, not where it wants too; therefore, fiber is part of that inter relationship same as reinforcement. I have seen plenty of concrete slabs of all types crack all over due to one or more of those items being not done right or done wrong.

One common example is control joints: If they are cut the morning after placement of the concrete, to bad the cracks where they want to be are already there even if you can't see them. Wait a few days. That is why on large dollar projects they have Professional Quality Control and Assurance at all stages; from the raw ground to the end of the curing process. Small jobs like the OPs, he is the QC. It is not arduous to get good concrete, just takes attention to detail. I can show you many slabs done 30-20 years ago with no re-bar or wire mesh that have no visible creaks today. I did a driveway at one of my houses, 24' wide 60' long full 4"+ thick, 4,000# concrete dosed with fiber and 5% air entrainment. 30 days after placement parked my 40' motor home on it and drove a loaded ten yard gravel truck over it. I put my money into the sub-grade.

Read one or all of those books.

Ron

Hey Ron, when do cuts need to made?

Do you want an all expenses paid trip to my back yard to lord over whatever unsuspecting fool I hire for concrete?

 

[Tractor Seabee]

Hey Ron, when do cuts need to made?

Do you want an all expenses paid trip to my back yard to lord over whatever unsuspecting fool I hire for concrete?

As soon as you can after finisher is done, large slabs hey start right behind the finishing. Demand they use what is called a soft cut saw. Even if you have to put up lights. I have followed saw cutting till well after midnight.

I am a peaceable man, hate arguments with no-it-alls. I and my transportation would cost more than the slab is costing you. Read my last, that is why a lot of small jobs fail. Best insurance is to hire contractor's that are ACI certified. At least you know they have some formal training in the subject. Probably won't happen in real rural areas where Ole' Bubba is the only resource. Get references and check the work (actually eyes on) on his last few projects.

Ron

 

[Tractor Seabee]

As soon as you can after finisher is done, large slabs hey start right behind the finishing. Demand they use what is called a soft cut saw. Even if you have to put up lights. I have followed saw cutting till well after midnight.

I am a peaceable man, hate arguments with no-it-alls. I and my transportation would cost more than the slab is costing you. Read my last, that is why a lot of small jobs fail. Best insurance is to hire contractor's that are ACI certified. At least you know they have some formal training in the subject. Probably won't happen in real rural areas where Ole' Bubba is the only resource. Get references and check the work (actually eyes on) on his last few projects.

Ron

Add on: Most areas close to cities have testing companies that perform what I used to do. Remember start with the sub-grade. Best concrete inspection/surveillance does not solve the first potential problem area.

Ron

 

[goeduck]

Best insurance is to hire contractor's that are ACI certified.

Good advice. Do you know if any of the ones around here are ACI certified? Next year or the year after I plan to help and my shop.

 

[Steppenwolfe]

Good advice. Do you know if any of the ones around here are ACI certified? Next year or the year after I plan to help and my shop.

Call your local concrete supplier or plant. Ask for a sales rep, they can help you out and will know who the good contractors are. It's their job and I always have good luck doing that.

 

[goeduck]

Call your local concrete supplier or plant. Ask for a sales rep, they can help you out and will know who the good contractors are. It's their job and I always have good luck doing that.

I sure can do that but Tractor Seabee and I are in the same county and I am hoping he has an independent opinion. I may get good advice from the concrete supplier or I may just get the name of their highest volume guy.

 

[Tractor Seabee]

I sure can do that but Tractor Seabee and I are in the same county and I am hoping he has an independent opinion. I may get good advice from the concrete supplier or I may just get the name of their highest volume guy.

Steppenwolfe has a good idea. All the big suppliers have certified CSI at the batch plant level and should know who is out there. For the job site; a certified inspector you will not find or could afford for small projects, only 2 statewide. Construction Flatwork Finishers and Technicians have the knowledge base to do what you need. As example if the base forms, and/or reinforcement is not properly ready they will inform you with recommendations for correction. Stopping work is then your decision. There are a lot of those certified people employed by contractors and construction testing companies. Mayes Testing is one I have worked with extensively in the past. They do a lot of work on the Army and Navy bases. Unfortunately they may not want your small of job.

Certification is an individual not a contractor company program. Two things you can do: find a contractor that hires certified workers (at least supervision) or become knowledgeable on your own to do your own inspection. I am no longer in business so do not carry E & O insurance any more. Finally retired after 70 years in the construction world. Folks with my past are consumed on the big projects booming in the area. Contractors doing military projects have 1 or more construction QC specialist(s) for each contract.

ACI has a good web site and you can find or verify certification. They do not have names on the web site but you can contact by phone or email.

Ron