Crack Risk Assessment in Massive Structures
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This Master s thesis is the extended version of the project assignment done for TKT4530- Concrete Technology, Specialization Project, and has mainly two parts. The first part studies the effect of the seasons on crack index for new casted concrete which is alongside existing concrete bearing on bedrock(highly stiff element). The second part studies the of effect of mechanical parameters of concrete on the crack index and generation of sensitivity analyses from the results taken from the CrackTeSt COIN program. The project for, construction of New Verma Powerplant is an on-going project, and the simulations and results in this thesis are for this specific project. Section 2.Theory covers a wide range of theory background supporting simulations and results done in the CrackTeSt COIN program. Theory topics are relevant for this thesis and most significant topics are selected and elaborated. Due to time constraints and the limited scope of this semester, not all necessary theory topics are included in this thesis report. In both parts (section 3 and 4), several simulations have been performed in the CrackTeSt COIN program. The simulations generate more than 300 pages of results. This number has been decreased to a minimum, and only the most important results are attached in section 7.Attachements. For section 3 (3.Effect of Season on Crack Index), two type of cements were used, both ANL FA (16,6% FA) and ANL FA+16 FA (33,3% FA). Obviously, the second type of cement generates less heat than the first, and thus leads to a lower crack index for this type of cement. The effect of external restraint is huge, and even when using cement type ANL FA+16 FA (33,3% FA), the crack index is higher than critical, specifically 1,0. A crack will definitely occur. The report suggest some measurements which can be undertaken in order to prevent cracking of the new concrete. For section 4 (4.Effect of Mechanical Parameters on Crack Index), first the ANL FA+16 FA (33,3% FA) cement type was used. The results shown that the crack index is higher than 1,0 even for highest tensile strength used in this part. Therefore, the 40% Fly Ash type cement is used in the simulations. The sensitivity analysis done for section 4, shows how the crack index varies when we change the mechanical parameters of the concrete. Only E-modulus and tensile strength of concrete are studied and changed individually to compare the results.