I currently have a gravel driveway that I would like to upgrade to concrete. It has had several layers of gravel over the decades and been driven on for at least 50 years. Any concrete slab on grade I have ever designed has always included a gravel base over the subgrade. However, I am thinking...
The concrete will be used for a base slab of an oxidation ditch at a wastewater plant. The contractor will be getting trucks from both plants during the slab placement. It will be a large pour and 1 plant will not be able to keep up with it hence his proposal to use 2 plants. We have told him...
We have a large concrete placement planned and the contractor wants to use 2 different batch plants. The issue is each plant has a different proposed mix. Each mix by itself would be acceptable but I don't know if it would be a good idea to mingle the 2 mixes. One mix proposes the use of Type 2...
The PADOT min. embedment is 1'-0" unless it is a single row of piles in which case it is 1'-6". Probably because I have been using that standard for over 30 years that 6" seems skimpy.
Just curious but did the contractor make a concrete submittal and, if he did, did it show entrained air? Was there a clerk of the works or inspector on the job when the concrete was delivered?
I pretty much agree with everything that bridgebuster has told you. Only thing is that some states, PA for example, do not require Team Leaders to be PEs. I spent several years inspecting bridges in NY and PA and absolutely loved it. I always worked for consultants and not a DOT which meant you...
Our firm designs a lot of below grade tanks for wastewater plants and we quit using the ground water relief valves over 20 years ago after we actually had a valve malfunction and a large clarifier floated about 2 feet out of the ground. We now use the tank weight exclusively to counter act the...
The company I work for does a lot of WWTP work involving the design and construction of concrete tanks and we never put vapor barriers below the tank slabs. It has never resulted in a problem of which I am aware.
Listen to your contractor. There is a chance of blistering and/or delaminations when you hard trowel air entrained concrete. See ACI 302.1R 5.7.1. I would recommend keeping the air and either eliminating the trowel finish or minimize your water content(slump) and delay the troweling until all...
I cannot find our office copy of the 1993 AASHTO PDG and have been asked to do a small pavement design. What I really need is Figure G.7 and Figure G.8 from Appendix G. If someone could scan them for me I would really appreciate it. Thanks!!
I am doing a pavement design and cannot find our 1993 AASHTO Pavement Design Guide. What I really need is Figure G.7 and G.8 from Appendix G so if someone could scan them for me I would really appreciate it. Thanks!
