ROAD CEMENT CONCRETES BASED ON MODIFIED ADDITIVES OF NEW GENERATION

2018;
133-137
1
Lviv Polytechnic National University, Department of Roads and Bridges, SikaUkraina LLC
2
Lviv Polytechnic National University, Department of Roads and Bridges
3
Lviv Polytechnic National University, department of Highways and Bridges
4
Lviv Polytechnic National University, department of Highways and Bridges

The modified concrete mixes design and cement concrete with the given operational parameters was developed. During the experiment, cement concrete was obtained from concrete mixtures of various compositions with modifying additives of a new generation containing a superplasticizer based on polycarboxylates and an air-absorbent additive. Superplasticizer was injected into a concrete mix with water in a quantity of 0,6; 0,8 and 1,0 % of the mass of cement, and the additive-aeration – in the amount of 0,1 % of the mass of cement in all the components of concrete. The influence of modifying additives on the
properties of road cement concrete has been investigated. The effectiveness of their use in road surfaces is shown, which provides improved technological parameters, increased strength and durability. Air-absorbent additive-airant, in combination with a superplasticizer, allows to enhance the plasticization of the concrete mixture, as well as increase the frost resistance and waterproofness. The introduction of a modifying additive from 0,6 to 1,0 % ensures an increase in the strength of concrete in the early hardening period (2 days) from 8,7 to 11,0 MPa. After a month of hardening the strength of such concrete is 39,2 – 39,9 MPa, which corresponds to the class of concrete B30. The use of a modifying additive during the preparation of a concrete mix allows the design of concrete with a water-cement ratio, which will reduce the open porosity of the concrete, increase its density, and thereby prevent the formation of highlands on the surface of concrete. When introducing a modifying additive, porosity is reduced by 1,4-2 times, which correlates with the results on the strength of concrete. The techno-economic efficiency of the use of road cement concrete on the basis of new generation modifying additives was determined and the construction of cement-concrete coating was found to be cheaper by 1,6 times the construction of road pavement from asphalt concrete in comparison with the cost of construction and installation work.

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