High strength modified concrete for reconstruction of engineering structures and networks, roads
Abstract
The use of such a material as concrete as part of various structural elements of road construction facilities is quite widespread, promising and is constantly being improved. The important properties of concrete used in the construction and reconstruction of engineering structures and networks, streets and roads of road management is its ability to withstand long-term effects of dynamic loads in combination with various atmospheric factors. The purpose of the article was to study the possibility of using ordinary Portland cement in concrete used for reconstruction and rehabilitation of engineering structures and networks, roads. For this, it is necessary to reveal the effect of mechanical activation of the binder (portland cement + microsilica + plasticizer Super PC + polypropylene fiber) on the mechanical characteristics of cement stone (the first series of experimental studies).
In the experiment, ordinary Portland cement PCII/А-Ш was used, the consumption of microsilica varied in the range of 0...10% of the cement mass. The concentration of Super PC superplasticizer was assumed to be equal to 0 ... 1% of the mass of the binder. Polypropylene fiber with fiber sizes from 6 mm to 12 mm and in the amount from 0 to 1% was used as an additive. The suspension activation time was 120 seconds. Compression tests of samples were carried out after 3, 7 and 28 days. For control, samples of similar compositions were prepared, the binder of which did not undergo activation.
It was found that the combined study of the influencing factors – mechanoactivation and microsilica, with a certain concentration of Super PC and polypropylene fiber, allows to increase the strength of cement stone at the age of 28 days from 62.41 to 113.4 MPa, i.e. more than 1.8 times compared to the control. This will make it possible to use the specified composition of cement binder in the future for the preparation of high-strength concrete in reconstruction and rehabilitation of engineering structures and networks, roads.
