THE INFLUENCE OF BASALT FIBER AND SUPERPLASTICIZER ON THE STRENGTH OF CONCRETE FOR RIGID PAVEMENTS
Authors:   Odessa State Academy of Civil Engineering and Architecture, Kroviakov S.O. , Shestakova L.E. ,   Odessa State Academy of Civil Engineering and Architecture
Published: December 2023

The experiment was conducted according to a 15-point symmetrical plan. The following factors of the fiber concrete composition of the rigid pavements were varied: the amount of Portland cement (from 290 to 350 kg/m3), the amount of BAUCON®-basalt fiber with a length of fibers 12 mm and a diameter of 18 μm (from 0.9 to 1.5 kg/m3), the amount of superplasticizer STACHEMENT 2570/5/G (from 0.6 to 1% of the mass of cement). All mixtures had equal mobility with a cone slump of 2..3 cm, which was achieved by selecting the amount of water with appropriate adjustment of the fiber concrete composition. It was found that the W/C of a concrete mixture of equal mobility decreases as expected with an increase in the amount of Portland cement. The W/C of the mixture is reduced by increasing the amount of superplasticizer to 0.9-1.0% of the cement mass. When increasing the amount of basalt fiber from 0.9 to 1.5 kg/m3, W/C practically does not change. The compressive and flexural strength of fiber concrete at the age of 3 and 28 days was determined. It was found that the general nature of the influence of various factors on strength in early and project age is similar. The compressive strength of the investigated fiber concrete at the age of 3 days is 65-68% of the level of their strength at the age of 28 days. The flexural strength at the age of 3 days is 73-75% of the 28-day strength. The strength of fiber concrete is expected to increase due to the increase in the amount of Portland cement in the composition. At the same time, the strength increases more noticeably in the project age. When increasing the amount of basalt fiber from 0.9 to 1.5 kg/m3, the compressive strength increases insignificantly. Increasing the dosage of superplasticizer from 0.6 to 0.9-1% causes a decrease in W/C, due to which the compressive strength of fiber concrete increases. The strength at the age of 3 days increases by 2.3-2.6 MPa, at the age of 28 days increases by 3.2-3.8 MPa. The level of flexural strength is most significantly affected by the amount of cement in the composition. The flexural strength of fiber concrete at the age of 3 days increases by 0.5-0.6 MPa due to an increase in the amount of basalt fiber from 0.9 to 1.3-1.4 kg/m3. At the age of 28 days, the strength increases by 0.7-0.8 MPa. Changing the amount of superplasticizer within the factor space of the experiment does not significantly affect the flexural strength of fiber concrete. Thus, the amount of basalt fiber BAUCON®-basalt 1.3 kg/m3 can be considered rational in the investigated fiber concretes. The amount of superplasticizer STACHEMENT 2570/5/G of 0.9% by weight of cement is also rational. Fiber concrete with compressive strength from 40 to 55 MPa and with flexural strength at bending from 4.5 to 6 MPa, depending on the amount of cement in the composition, was obtained thanks to the use of a rational amount of basalt dispersed reinforcement and superplasticizer.