Self-Compacting Concrete (SCC) is a pioneering concrete that can gush beneath its own load, filling the formwork, and achieving full consolidation while maintaining sufficient cohesion to handle the concrete without segregation or bleeding issues. To develop EPS- fiber reinforced SCC, waste materials such as Expanded Polystyrene Beads (EPS) and waste plastic fibers (Polyethylene terephthalate (PET)) were incorporated. This study investigated the response of SCC to the incorporation of different ratios of PET fibers (0.35%, 0.5%, and 0.75%) and 10% of EPS particles and its impact on fresh and mechanical properties of SCC mixtures. Five SCC mixtures were designed, including the reference mixture, 10% EPS mixture, and three volume fractions (Vf) of PET mixtures. Test results indicated that EPS particles had an optimistic effect on fresh properties and a slight negative effect on mechanical properties. While PET fibers revealed a slight negative impact on fresh properties, they also improved mechanical properties. The highest and lowest values in fresh properties tests, including slump flow, T50, V-funnel, L-box, and sieve segregation were (780mm for (E %10) mix, 5.4 seconds for (0.75% f) mix, 19 second for (0.75% f) mix, 0.85 for (E %10) mix, and 10.77% for (R) mix), respectively and (670mm for (0.75% f) mix, 1.8 second for (E %10) mix, 6 seconds for (E %10) mix, 0 for (0.75% f) mix, and 3.28% for (0.5% f) mix), respectively. While, the highest and lowest values in mechanical properties tests, including density, ultrasonic pulse velocity (UPV), compressive strength, and splitting tensile strength were (2305 kg/m3 for (R) mix, 4.2 km/s for (R) mix, 48 MPa for (0.5% f) mix, and 3.66 MPa for (0.5% f) mix), respectively and (2170 kg/m3 for (0.5% f) mix, 4.03 km/s for (0.75% f) mix, 31 MPa for (E %10) mix, and 2.33 MPa for (E %10) mix), respectively
A study was undertaken to produce lightweight aggregate concrete using artificial lightweight aggregate (Lytag) made from sintered fly ash. Cement or fly ash-based geopolymer was utilized as binder material, and its effect on the properties (compressive strength, water absorption, and thermal conductivity) of lightweight aggregate concrete was investigated. Two mixes were designed (using the absolute volumes method) and produced at a density of around 1350 kg/m3 as cement lightweight aggregate concrete and geopolymer lightweight aggregate concrete. Fly ash and an alkaline solution (sodium hydroxide and sodium silicate) were used to produce the geopolymer paste. The results indicated that the compressive strength, water absorption, and thermal conductivity of lightweight aggregate concrete made with geopolymer paste were better than those made with cement paste. An increase in compressive strength by about 49% and a decrease in water absorption and thermal conductivity by about 36% and 25%, respectively, were noticed in fly ash-based geopolymer lightweight mix compared to cement lightweight concrete mix.
The purpose of this research is to produce a modified SCC that involves the incorporation of expanded polystyrene (EPS) and waste of plastic type (PET). The goal is to minimize the weight of the material while simultaneously improving its brittleness and reducing the environmental impact. The study focuses on two methods for reducing the weight of structural elements by using EPS beads, which create voids through concrete, and the second method is making a hollow through the element. This study included designing and investigating four concrete beams under concentrated static load. The parameters were hollow position and material types. The results showed that the offsetting hollow from the center of the beam enhanced the ductility index by 10% and increased the load capacity by 10%. Adding EPS beads reduce the concrete density by 11.5% and load capacity by 22%. Toughness was improved by using plastic fiber due to the mechanism of crack bridging. The crack pattern had been changed due to the utilization of waste material, and enhancement was observed through experimental tests by making smooth cracks and changing the probability of sudden failure when using GFRP rebars. It was found that the optimal quantity of EPS was 2 kg to produce SCC in accordance with code requirements. No debonding or slip was observed during monitoring, as evidenced by the absence of spalling or cracking around the reinforcement.