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Posted: Wed Feb 29, 2012 3:07 pmPost subject: Summary of E-Conf -Days 2 & 3 |
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Strict Quality control - - - A Key to Durability
The mood in the e-conference on Durability of Concrete has really picked up , and why not , since talk is on Engineer's most essential tool i.e. CONCRETE , which besides providing 结构强度(compression front ) , could be poured into any form / shape as 每美学的要求。我个人觉得that a religious QC is the key to success in maintaining concrete durability as noted at top.
On day 2 and 3 , we have many interesting postings - - - - - - -
Er Suraj Singh has uploaded Note on Supplementary cementing materials which is good for budding engineers as well as veterans equally. Admin sefi has already provided gist of this.
Mr Vijay Kulkarni while responding to the querry on EPS concrete refer it as useful and eco-friendly material in terms of its light weight, thermal insulation and fire resistance apart from its availability potential in India but its use needs to be limited to Non- Load Bearing walls only.
Er Naresh Reddy in his posting feels that Ancient structures give us true lesson of Durability but innovative solutions for Durablity must be thought of.
We also got very informative posting from leading bridge design expert Mr Alok Bhowmick and I must compliment him for the substance of the posting.While discussing the durability aspects of Bridges in various countries with regard to aggressive environment, extreme weather conditions, the bridges in India in most part of country suffer from poor workmanship rather than other factors viz chemical environment/inclement weather conditions.
Postings from Dr NS is response to +1000yr concrete.He also appreciated the work of Er Suraj singh in this area.While responding to posting of Mr Jignesh , the importance of proportions of conc mix ingredients is duly acknowledged for durability.Responding to the posting from Er Alok Bhowmick , he also feels that for proper workman ship , Training is essential for all those handling the conc workwhile reminding the most forgotten aspect of durability/strength for concrete i.e. proper CURING.
Er Iyer also appreciated the need for proper mixing /pouring of concrete ingredients also emphasizing on Testing of concrete.Er Milap Singh expressed satisfaction over information regarding newer material like EPS concrete
The exhaustive posting from Madam Alpa Sheth is a reality of present scenario of construction in terms of pace without quality adherence.. Many RMC suppliers also lack culture of record keeping,QC and integrity . There is no check over silt content and source of ingredient materials.Concrete do not achieve strength even after 48 days.Madam Alpa feels that there is adequate knowledge available with us but problem is of attitude and motivation. I think her views provide every Engineer /workman related to concrete production to retrospect .(Admin sefi also responded to this posting expressing the need of strong law citing example of case document 962D of Council of American struct Ers)
Er Jignesh expects specific discussions on durability of concrete under sustained high temp , severe conditions chemical attack and water resistant.Er Padmanabhan .G , while lauding the organisers of e conf need expert views on concrete durability at sites having sulphate and chlorides and how to classify the site vulnerable to conc due to such chemicals.Er Vikas Pai feels that it is Owner's responsibility too for strict QC procedure / provisions
Responding to Madam Alpa 's write up ,Dr NS expressd that rock dust and foundary sand can replace fine aggregate while expressing his deep concern over the RMC not meeting required strength.He feels that IS 456 needs to address the conc strength at 56 days for conc with fly ash/similar materials.
Er Jignesh must be appreciated for his active particaipation in discussions Thru his posting needs to know about the effects of sustained temperature on conc produced with flyash 20 percent content since not much is available in literature.He also cited such situations where sustained high temp on conc exist at m/c in various industries. ( Er Malayala Sivaram kapil later responded to this query saying that Heat of Hydration will reduce with use of Flyash and use of GGBFS is still better)
Er Alok bhowmick once again pleased us on sefi by posting a ppt presentation on Durability provisions contained in latest bridge Code IRC -112 (2011) and deserves special thanks.
Posting from overseas by Er Moruf O Usuf list various aspects of using flyash in concrete ,favorable/unfavorable.Er Arun Kashikar ,based on his experience with RMC suppliers in Mumbai state that crushed sand (due to non availability of river sand ) must be Zone II VS I sand.RMC is based on SEVERE exposure condition but for temperature,it is not at all controlled.Er Gattani want Govt to explicitly prescribe QS for RMC plants.
Posting from another veteran Er K C Francis , a well known sefian, also list the steps to achieve durability with special emphasis on Curing and maintaining stipulated W/C ratio.
Posting from Er Amit Haridas (thru admin) is encouraging . It is felt that profit making at large has crept into conc production even though we have better construction materials presently.Curing is most neglected and forms are removed quite early than stipulated time , all affect durability /longevity.Lack of training is also a cause against durability.
Looking forward to more participation and with thanks & regards
vikramjeet Conf - Raconteur
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