Kindly see attached specs (QCS 2010), according to this specification, target strength shall be calculated depending on grade of concrete.. ( which is very much practical too)... Also, they clearly referred target strength as required strength.. see clause 7.
I GUESS answer to my question is...
What is difference between Target Strength and Target Mean Strength ???
As for required strength (Target strength) is given as (Characterstics strength + 1.64 * S.d).. this 1.64 may vary as depending on different criteria.
I had also seen some specs defining Target mean strength with totally...
Dear Mr. Ron, thanks for correcting me.
Just want to know, as UPV is to check uniformity of concrete cant it interpret segregation of concrete or radiography is only option?
As per Qatar Specs.
For upv
The use of data from nondestructive testing devices, such
as impact hammers or probes...
For pavement design we have backfill material with ascending values of CBR, eg. subgrade CBR: 15 %, Aggregate Base 80%.
What will be effects if bottom layer has high CBR with respect to succeeding layer?
Also,I want to know what is significance of permeability of soil ??
if its casted sample 28 days is generally followed for permeability, but in case of core cutting, contractor generally delays to 56 days hoping concrete to give better results.. but for core cutting from hardened concrete, I dont think durability requirement is passing criteria.
Earlier I was in a project in Mumbai, India, and natural sand was totally banned there.
We had mix with 100% replacement with crush sand and it is complying it with all requirements like water permeability and RCPT.
I think its very common and you can contact local RMC to assist you in preparing...
More strength gain often can be seen with mix design with GGBS or fly ash.. more percentage of ggbs/ fly ash results in prolong hydration and reduction of hydrooxide resulting in higher strength in longer duration. Sampling deficiencies or damage for cube tested in earlier duration may be other...
Cube sampling was done before discharge for start of placing concrete in structure? if that's the case then its clear indication of water added to truck after sampling of concrete.
Such high slump is not possible without plasticizer.. anyways its hand mix or RMC.. nowadays nearly all mix are...
General practice is taking core after 14 days, but due to urgency of work and as consultant do not want to rely on schimdt hammer or other NDT test, the only solution was to cast a panel along with Lining of shaft and then remove panel from lining to take core (in order not to damage lining) we...
thanks Mr. yaschief.. I had not read rules before.. i post it i diffrent forum with a thought that more people can view my post...
I deleted it from other forum.. Thanking you again
thanks for your superb reply... after reading responses here my perception changed.. below are more specific details of coring..
Core size 100 mm dia, length 100 mm.
Maximum size of aggregate : 10 mm
Sample represent 1 batch of concrete. at time of coring panel was dry and water is added...
Recently I come across 2 concrete core test results (tested in different dates) where 28 days strength was lower by 10 MPa to 7 days... I do not have any justification to it, only reason can be honeycomb or air voids, or low quality aggregates used for concrete.. but this cases are not...
Recently I come across 2 concrete core test results (tested in different dates) where 28 days strength was lower by 10 MPa to 7 days... I do not have any justification to it, only reason can be honeycomb or air voids, or low quality aggregates used for concrete.. but this cases are not...
