INFLUENCE OF X-Mesh POLYPROPYLENE FIBER ON THE PROPERTIES OF ROAD CONCRETE

Abstract

Road and airfield pavements are subject to constantly increasing vehicle loads, aswell as aggressive liquid media and temperatures. Under these conditions, the search for andimprovement of new types of cement concretes that are able to withstand these influences for severaldecades is urgent. First of all, such concretes include fiber-reinforced concrete (FRC). The articlediscusses the advantages and disadvantages of using various types of fiber in the technology of heavycement concretes. Basalt or polymer fibers are most often used in road concrete. Steel fibers are notcommonly used due to possible corrosion of metal fibers. The use of basalt fiber gives an effect ifthere is a large amount of it (more than 6 kg/m3). But this leads to difficulties in their uniformdistribution in the volume of concrete mixture and increases the cost of concrete. Therefore, the useof polymer fiber is promising. It is shown that there is no consensus regarding the effectiveness ofusing fibers longer than 20 mm. Therefore, in the experiments, we used X-Mesh polymer fiber withlengths of 23 and 39 mm, with a fiber diameter of 100...150 µm. Experimental studies have shownthat X-Mesh fibers can form a structural framework within concrete. Therefore, when this fiber isintroduced into the composition of concrete, its compressive strength does not decrease, in contrastof concretes with other types of fiber. In addition, X-Mesh fiber disperse reinforces the concretestructure, which leads to an increase in flexural strength by 22 %. FRC strength studies have shownthat the optimal amount of X-Mesh fiber is 1.5 kg/m3. It has also been shown that polypropylene fiberswith lengths of 23 and 39 mm have the same positive effect on the properties of road concrete. It wasfound that X-Mesh fiber is capable of entraining an additional amount of air, which leads to adecrease the average density of concrete by 3 %, but increases its frost resistance. Despite theadditional air entrainment, the water absorption of concrete does not exceed 2.5 %.