Cement composites modified with polypropylene fibers and type II additives
Agnieszka Ślosarczyk, Zofia Bekier, Katarzyna Wika
Quarterly No. 4, 2013 pages 282-287
DOI:
keywords: cement composites, polypropylene fibres, pozzolanic and hydraulic additives, mechanical properties, scanning electron microscopy SEM
abstract In the article, three different type II additives (fly ash, silica fume and slag) were used in order to improve the adherence of polypropylene fibres to cement mortar. Estimation of the level of fibre adherence to the cement matrix change was conducted on the basis of mechanical research of the composites, as well as observation of the interfacial transition zone between the fibres and cement paste in scanning electron microscopy. It was shown that the mechanical properties of cement composites modified with polypropylene fibres strongly depend on the type of pozzolanic additive and compactness of the interfacial transition zone between the fibres and cement paste. The obtained values of fracture toughness of the cement composites proved that during the whole research period (180 days), the presence of 0.5 vol.% polypropylene fibres, regardless of the cement matrix applied, improves the fracture toughness of the cement matrix. However, two ranges of reaction between the cement matrix and the fibres were observed; the first up to 56 days of hardening, where the fibrocomposite properties depend, besides the fibre properties, on clinker fine-crystalline phases of cement paste. The second one - after 56 days of bonding, where the composite properties depend mostly on the pozzolanic and hydraulic additives.