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Hi, I hope someone can enlighten me on what is the reason for ASTM to change the limit of heat of hydration value on Table 4 from 255kJ/kg @ 3days to 335kJ/kg @ 3days? This is a huge increase on the limit making the common type 1 cement compliant to type 2-MH as well. Will this change leads to...

@GeoEnvGuy, some articles are mentioning (no elaboration) that pavement can be placed within 3 to 5 hours after pouring. So I am thinking that you do not need to wait for the flowable fill to fully harden before applying any load.

We are planning to use a flowable fill as alternative backfill (subgrade level) on our utility trenched located on major roads. My major concerns are the following: 1. How long would it take (hours?days?) for the flowable fill to sufficiently harden before we can place a cement treated base on...

Is there any reference document that provides guideline on sizing of blow off assembly as per main water line diameter? Is there any reference computation? For example, can a 600mm dia. main line have the same size of blow assembly with a 2meter dia. main line?

Hi All, I would like to ask the opinions of you guys on which is the better material to be used as sealant for the sluice gate in our wastewater treatment facilities. Is it EPDM (ethylene propylene diene monomer (M-class) rubber) or Polyurethane type? The thing is of course this will be exposed...

Can Sand cone method be performed in a compacted granular fill material like sand upto maximum gradation size of 6mm? Are there any other more efficient means of determining field density for such material?

@killswitchengage Will this problem occur when the compacted fill layer is granular in nature or free draining like sand? Does water ponding really happens in a compacted granular fill?

@ fattdad So what can you suggest to mitigate the problem? Since we have an unfinished backfill and we still need to put several lifts before we reach our subbase course (our trench is located on major roadways subjected to Truck loadings) but then it was expose to a heavy rain, what is/ are...

So if my backfill on our pipe trenches was properly compacted at some point on the trench depth then it suddenly subjected to a heavy downpour of rain, water from the rain may pond from some time at the compacted layer reflecting the effectivity of compaction done right? What do we need to do to...

@ Okiryu Thanks for your reply. So what you mean is that even the soil is already compacted, its maximum dry density can change significantly when exposed to rain prior to field density test? Or you mean that rain can have an effect if the backfill material was exposed to it prior to...

Hi everyone. My question concerns the backfill on our pipe trenches. Our Contractors always say that the reason they are not utilizing the native material as backfill to our trenches is the problem with rain. They are saying that when their compacted backfill is exposed to rain (I expect...

@ Ron 1. I think the reason why our specification indicates the use of flooding because of the limited width of our trenches. We only have 6 inches allowance on both sides of the pipe. I think no Mechanical compactors can perform on such a small space. But can we do manual tamping then? 2. We...

Hi All, I am working as a Standards Manager in a water utility Company and currently we are having issues on the applicability of the backfill material we are using on our trenches and the right compaction method to be applied. I have attached a drawing of a typical trench section. As you can...

Any reference standards or documents to prove the usage of gravel as bedding for steel pipes having this diameter of 900mm?

Hi to all, I would like to ask if one can use gravel as bedding for a 900mm diameter steel pipe. If yes, what will be the size limit for the gravel to be used? Can you guys site any reference standards or documents to prove this usage? Thank you for those who can answer.

My choice is #3 as well. But it must be noted that the building you mentioned will also act as "surcharge load" and its effect must be added to the value of "H" in your load combination.

@bridgebuster and yakpol - Thank you very much for your replies.

Hi all, I am new in the design of bridges and I would like to ask for opinions regarding the design of longitudinal beams directly supporting the slab above. Is it fine to subject the longitudinal beam to the full load of an MS18 truck loading/ lane loading for example (i.e. 324kN gross...

@LuisUgarte , thanks for the response and the attached paper. Based on it, do you think that the resulting spacing and size of bolts/ weld to use is on the conservative side using the mentioned approach? @Hokie93, thanks for the response as well. That's a direct equation for computing the shear...

@BAretired Thanks for the response. For the single angle section, the rmin you're saying is equivalent to rz or the minimum of rx and ry?