This paper deals with the possibility of the improvement of pervious concrete properties by incorporation of different types of fibres and studies the effect of short duration vibration of pervious concrete properties in comparison with compaction with wooden lath and hammer. Ten mixtures of pervious concrete were prepared, five of which were compacted with wooden lath and hammer and five by short duration vibration. Density, porosity, permeability and mechanical properties were tested for in hardened pervious concrete specimens. It was concluded that mixtures compacted by short duration vibration had better mechanical properties due to the formation of a viscous layer at the contact surface between the aggregate grain and the cement matrix during the compaction, as well as pore-related properties. The addition of fibres negatively affected porosity and permeability but generally improved mechanical properties of concrete. The positive effect of fibre addition was more emphasised in cases of vibrated mixtures.

This paper examines the use of sheep wool and recycled aggregates (recycled concrete aggregate, reclaimed asphalt aggregate, recycled brick aggregate) in mortars. Nine cement mortars were prepared: a reference mortar with natural aggregate and no fibers, and eight mortars with 30% recycled aggregate, either fiber-free or micro-reinforced with 0.1% by mass of sheep wool fibers. The study investigates the effects of these components on the workability, mechanical properties, and microstructure of mortars. Micro-reinforcing mortars with sheep wool fibers or partially replacing natural aggregate with recycled aggregates reduces workability by up to 32%. Mortars with recycled concrete and recycled brick aggregates showed increased compressive and flexural strength compared to the reference mortar. The combined formulation (recycled brick with sheep wool micro-reinforcement) achieved the highest compressive strength, increasing by 24.3% while maintaining excellent flexural performance. Three-point bending tests with displacement control revealed improved post-crack behavior and greater ductility in fiber micro-reinforced specimens compared to those without fibers. The results support the use of sheep wool fibers in mortars, demonstrate the satisfactory performance of recycled aggregates, and indicate promising potential for formulations combining sheep wool fiber and recycled aggregate as sustainable and waste-reducing alternatives in mortars.

Corrosion of reinforcement is one of basic destruction mechanisms of reinforced concrete structures. In that sense, the most affected structures are those by the sea, especially their parts subjected to cycles of wetting and drying. Chlorides penetrate to concrete mostly by diffusion, faster if the concrete is more permeable, destructing reinforcement passive protection and causing its corrosion, reduction of reinforcement cross section and bearing capacity of the structure. Retardation of chloride corrosion that causes structure degradation in marine environment can be achieved by the usage of quality concrete with enhanced strength and permeability parameters in regards to ordinary concrete. Mixes of ordinary and high performance concrete with different ratio of silica fume have been made. Compressive strength and resistivity to chloride penetration have been tested on the specimens 28 days after mixing. The resistivity to chloride penetration has been determined by fast chloride penetration test according to ASTM C1202 standard, using appliance that measures electrical conductivity of concrete specimens. Based on test results, the suitability of building reinforced concrete structures by the sea using high performance concrete has been analysed.

This study examined the influence of natural fibers on the physical, mechanical, and fire‐resistant properties of microconcrete, in comparison with conventional polypropylene fibers used in cement composites. The fibers were characterized by FTIR and TGA/DSC to assess their composition and thermal stability, and FTIR was also performed after thermal testing to evaluate structural changes. A reference microconcrete and six fiber‐reinforced mixtures with varying fiber types and dosages were prepared. Workability was evaluated in the fresh state, while tests on hardened specimens included water absorption and toughness, as well as the compressive strength, flexural strength, and the mass of the specimens, all three of which were measured before and after exposure to 400°C. To interpret the results, the microstructure of selected specimens was analyzed using SEM. The incorporation of natural fibers enhanced post‐cracking behavior and toughness while maintaining comparable compressive strength to the reference mixture. Fire tests demonstrated improved resistance to microcracking, confirming the potential of natural fibers to improve the toughness and fire performance of microconcrete.

U radu je istraživana mogućnosti primjene industrijske otpadne PVC piljevine kao djelomične zamjene za pijesak u mortu i betonu. U tu svrhu izrađene su mješavine standardnog cementnog morta i običnog betona u kojima je udio pijeska zamijenjen različitim volumnim udjelima PVC piljevine. Rezultati ispitivanja ukazuju na smanjenje obradivosti mješavina te trend smanjenja tlačne i vlačne čvrstoće savijanjem povećanjem udjela PVC piljevine u odnosu na referentni beton.