## 5 Conclusions  
The manuscript presents complex experiments and analyses that aim to support a new production technology of selectively curved concrete sewer pipes, which is being introduced by the company Prefa Brno a.s. This technology requires HPC-SCC of high strength and resistance against the most common aggressive environments. The presented experiment made it possible to successfully fulfil the first, important part of the project task, namely to design and verify several compositions of model mortars which will achieve very high strengths and resistance to sulfates. However, their resistance must be verified by additional tests which will simulate other possible stresses sewer pipes are exposed to at the point of application. Some of these tests are currently being conducted and the  
Figure 16: M3 after 285 days in the sulfate bath: (**a**) cracking on the longitudinal edge of a specimen; (**b**) a network of cracks in the corner of a specimen; the red line indicates a length of 1 mm. Figure 17: View of the front faces of the test specimens from M3 after 285 days in the sulfate bath—the front face surfaces tend to separate from the specimen cores. team of authors is planning to acquaint the scientific community with their results in the near future. The experiments have also provided some new general scientific and professional findings:  
* The best measure against the corrosive effect of sulfates proved to be the addition of metakaolin, which showed itself to be very effective already in the amount of 100 kg/m\({}^{3}\) (mortar M6) and significantly increased the mortar's resistance. A further small improvement was achieved after the metakaolin amount had been increased to 150 kg/m\({}^{3}\) (M7 and M8). The large amounts of metakaolin should not surprise the reader as these are quantities for model mortars. In the case of derived concretes, the metakaolin amount is 50 kg/m\({}^{3}\) in SCC6 and 75 kg/m\({}^{3}\) in both SCC7 and SCC8. * Finely ground SMS slag allowed the model mortar to reach a record compressive strength of 134.4 N/m\({}^{2}\) after 28 days of aging. However, its resistance parameters were significantly worse than those for MMs with metakaolin. This is surprising, since the amount of GBFS was quite high (100% of cement) and strength was excellent. However, metakaolin in the given amounts in the mortars (100 or 150 kg/m\({}^{3}\)) proved to be more effective anti-corrosion admixture for sulfate (sodium sulfate) environments. * The conducted experiments also included a test of the crystallization admixture Xypex Admix C-1000. Instead of the promised improvements, the crystallization admixture managed to spoil almost everything--from deteriorated consistency through limited compressive strength to the worst sulfate resistance (in all the essential monitored parameters) and did so not only in comparison to the other MMs, but also to ordinary M2, to which it was added. At the same time as the unflattering results of the application of the Xypex Admix C-1000 are discussed, it should be noted that it cannot be applied universally. It is only valid when using the same cement with the same w/c ratio, the same admixture dosage and, after all, the same sample of Xypex Admix C-1000. * For the first time ever, samples in the sulfate bath were monitored according to the principles of the graphical TBTC method. In summary, it can be stated that the application of this method was successful, i.e., the obtained results were expressed very clearly and were in excellent agreement with the results of other monitoring methods (relative length changes and relative mass changes of test specimens). * The TBTC method is described in the article in enough detail to allow anyone interested to apply it. The TBTC method is freely available to the scientific community. Conceptualization, I.T., D.K. and F.G.; methodology, I.T., D.K. and J.S. ; software, D.K. ; validation, I.T., P.S. ([PERSON]) and P.S. ([PERSON]); formal analysis, I.T. and D.K. ; investigation, D.K. and J.S. ; resources, I.T., D.K.