2 Comments

  1. The discussion was great and I really appreciate this review of principles we all know as a civil engineer, but sometimes forget to practice completely. The only thing, among the article I would like to have a complementary explanation is the layered concreting you talked about. Based on my experience, you can do in the manner you mentioned, while you are making sure that you will get back to place the next layer without long gap. I mean since you place the successive layers before previous layer starts hardening and getting dry it would be a good suggestion to gain smooth surfaces and prevent segregation or honeycombing. Otherwise, not only it won't help to have a homogenous concrete matrix, but also successive layers will not penetrate and merge to each other and consequently, later on when for instance beam section encounters with a bending load, the continuity of tension diagram will crack. It means that concrete will not act as a unique continuum resulted in imperfect transmission of shear stresses within discontinuation surfaces. Therefore, a kind of concrete major lamination will happen prior to micro cracking under compressive tensions which are more likely to be cause of fracture and failure in concrete.

  2. Yes, Obviously the concrete in successive layers must be filled/laid in within the initial setting period of the layer before, and also the surface must by scraped with the help of scraper a bit, before placing the new layer, as after compaction of the previous layer with Needle Vibrator a laitance may form on the top surface and it must be disposed off or later on it may act as the plane of separation as will act as Transition Zone. Thank You for your views on the article, I highly appreciate it. Keep visiting Techno Genome.

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