Olevych Y. Ultrarapid hardening Portland cement compositions and modified high strength concretes on their bases

The thesis is devoted to the development of theoretical bases of obtaining of nanomodified ultrarapid hardening Portland cement compositions for high strength concrete on their basis with improved building and technical properties. The possibility of development of such compositions on the basis of ordinary Portland cement for high strength concrete with using nanotechnological methods of the modification of cementitious matrix by introdution of nanoscale particles of C-S-H phase and polycarboxylate type superplasticizer is shown. The complex nanomodifier results in high water reduced effect with decreased interparticles distance, accelerated formation of hydrosilicate gel with a more homogeneous distribution of hydrates in a limited intergranular space. Effectiveness of nano-modified ultra-rapid hardening Portland cement compositions for high strength concrete under different curing conditions is confirmed. The compositions of the high strength concretes based on the nano-modified ultrarapid hardening Portland cement compositions were designed, their building and technical properties were investigated. It was shown that concretes based on ultra-rapid hardening Portland cement compositions allowed to provide development of low and zero energy technologies of precast concrete. Effective compositions of high-strength concrete for low-temperature regime of treatment have been developed on the basis of ultra-high-strength Portland cement compositions and technical and building properties have been investigated. Technical and economic efficiency of their use was calculated.