Our, not design and build,  A7 project is nearing completion, and I have to do falling weight defectometer (FWD) top of base and top of binder for designer validation. The design is HD 26/01 and uses figure 2.2, so the design is material choice and thickness. Not stiffness, so how does the designer validate his design? and how does he validate his design on a part built pavement that generally is still warm, but below 30 degrees C? It also occurred to my "catch up brain", that the temp is recorded by drilling into the pavement to 100mm. I do not pretend to understand the analysis procedure, but if the binder course is 55mm thick and at around 30 degrees C and I drill into it and further into the base for 45mm and record a temp, analyse that I dare you. Surely the methodology is for the pavement (all the layers) to be at the same temperature, is it me? I have been beating a drum about FWD and gathering meaningless info at great expense, to tax payers, you and me, regarding this TS requirement. So there is a change, a new requirement, in some tenders, appendix 1/5   we have to test top of base, top of binder, and now top of surface course. Well it seems my drum beating has backfired! Why is it not logical to look at the information gained, from top of base and top of binder and analyse it! Then take a step forward, perhaps the designers can't analyse the data? Perhaps they should have thought of that before implementing a half baked notion of design validation? Would it not be sensible to have trial sections built and program to let the base cool, then test it, then spray bond coat, lay binder, let it cool and test that layer, followed by the surface course and again let it cool and test. This could be a modified 929 trial, and could be tested during the contract period to measure any ageing effect. Then when available during laying without interrupting the process, top of base and top of binder when cooled and not bond coated could be tested and subsequently all the surface course. There would be no need to run off with FWD data to analyse every section of work, from the trial and its back analysis the deflection figures of all sections tested would be there for comparison. Of course relying on the surface course data is too late if it is wrong, but on a design and build contract the risk is between the contractor, the designer and the blacktop supplier. Why is the client introducing this interrupting process of FWD during laying? As i have blogged before the costs to interrupting the laying process to conduct FWD can be  more than the costs of  conducting the FWD, the people with the purse strings have not thought this out, why ? they don't have to think. And the purpose of this blog ? was to say yet again I am ensconced in the Marchback hotel, hence sleeping in England, the food is just sublime. I have seen Guinea fowl running around in West Africa, but never tasted it. The Marchbank Hotel is about good food and game in particular and what does the menu provide? guinea fowl. Plus rabbit, pheasant, roe deer, halibut, lemon sole, esk salmon, venison burgers, leg of lamb cooked in the Aga for ten hours, if three of you like lamb and only eat breakfast you may manage this lamb feast. and guinea fowl ? subtle type of pheasant. Breakfast of kippers in cream is an omega start to the day, scrambled pheasant eggs with crispy bacon (pigs not fed on fish meal) with home grown fried tomatoes. Catch me on a diet! Shadow grows no less!

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