The accumulation of wastes, especially plastic and car tires, has become a major problem facing society today. Therefore, through this research, these wastes were recycled and used to improve some properties of concrete. Recycled crumb rubber from car tires was used instead of sand as a partial replacement of 10%. The substitution was done by two methods: random and equivalent size substitution. As well, 1%polyethylene terephthalate (PET) fiber was added by the volume of concrete to improve some properties of rubberized concrete. Compressive strength, ultrasonic pulse velocity test (UPV) were conducted in this study to investigate the efficiency of PET rubberized concrete, as well the impact resistance test was also conducted to investigated the ability of PET rubberized concrete in term of energy absorption. Slabs of size (50cm×50cm×5cm) were utilized for low velocity impact test. The results indicated there were a reduction in compressive strength and UPV results were observed in PET fiber rubberized concrete the reduction were (37.47% and 5.4%) respectively as compared with PETC mixture and the result of dynamic modulus of elasticity show the same pattern of UPV result , in contrast there was an improvement in the impact resistance when PET fiber and crumb rubber were used it increased by(117.63% and 52.9% ) for random and equivalent replacement respectively as compared with PETC.
In this study, the structural behaviour of RC-deep beams of glass fibre-reinforced polymer (GFRP) rubberized concrete is investigated. Rubberized concrete is manufactured by replacing fine sand aggregate with rubber crumbs in volumetric replacement ratios. The main variables were the crumb rubber content (0%, 10%, and 20%) and the main reinforcement ratio. Tested Six samples of deep beams with different dimensions (b = 150, h = 300 mm, L= 1400 mm) were under a four-point load until failure. The parameters under investigation were the mechanical properties of mixtures, load-midspan deflection curves, toughness, and the load-strain relationship. The results indicate that the increased crumb rubber content led to a decrease in the mechanical properties of rubberized concrete mixtures. It was found that the behaviour of all samples of rubberized concrete affected the deflection load curve, the ultimate load, and the increase in deflection. The sample R2-10% Rub showed the highest toughness among the tested samples, with an increase of 301.6% compared to the reference.
Concrete is produced from millions of tons of Cement, which emits a significant amount of carbon dioxide from cement mills and contributes to global warming. Therefore, it is important to seek out less expensive and more environmentally friendly substitutes for OPC. While various substitutes are available, such as recycled glass, marble, silica fume fly ash, or agricultural waste like rice husks or wheat straw, the performance of concrete is significantly affected when bentonite is used as a replacement for Cement. This study aims to evaluate Jhelum bentonite, which is located at 32°56′ north and 73°44′ east longitude, as a replacement for Cement in different ratios (0:100, 10:90, 20:80, 30:70, and 40:60) to improve the durability of the system as more bentonite is used to replace conventional Portland cement, the workability, density, and water absorption of the new concrete all decrease. Compressive Strength, Tensile Strength, and flexural Strength of blocks and cylinders were tested after being cured for 7 and 28 days. Analysis of these strength tests revealed that the mixes containing bentonite were weaker after 7 days compared to 28 days, and the Strength of blocks was reasonable compared to cylinders.Keywords: Bentonite, Concrete, Compressive Strength, Tensile Strength.
There are various means of recycling agricultural wastes to maximize economic benefit from it. According to environmental statistics, agricultural wastes is one of the most dangerous types of wastes, especially in villages, because it is disposed of by burning. In this study, production of natural ash from agro wastes was carried out. Two types of agro waste ash were produced through burning and grinding process. waste date tree and waste reeds ash. The waste date ash (WDA) and waste reeds ash (WRA) were included in concrete by replacement of a specific portion of cement weight (5%, and 10%). Moreover, a blend of the two types of ashes were also considered. Furthermore, the natural ash was utilized in production of green concrete. Hardened density and compressive strengths at various ages (7, 28 and 56 days) were evaluated. The results in this research showed an excellent increase in compressive strength at ages (7,28 and 56) days. When measuring the compressive strength at the late age (56 days), DPA + WRA it was the best model used if it recorded the highest increase in it. Also, the use of WRA10% gave a good result, increasing its strength of the reference mixture and the rest of the mixtures also gave good and remarkable results in increasing the resistance, as the use of ash in these mixtures protects the environment from pollution and gives mixtures of higher resistance and can be used as a partial substitute for cement, except for DPA10%, so the usual mixture was better than it.
In recent years, a number of researchers have adopted the wet packing (WP) approach to design different types of concrete mixes. Particle grading is a key to the optimization of the wet compactness density; for that reason, all empty spaces that exist in between large-size particles need to be completely filled with particles of smaller size. Previously-conducted studies in this field have been focused on measuring the particle size distribution’s packing density (PD) of the of granular matrices is the purpose of investigating how to increase the PD of cementitious materials. Thus, literature lacks models capable of predicting the optimal PD value. The current study collected and analyzed 216 datasets in order to construct a model for accurate prediction of PD. The main datasets were organized into two categories: modeling datasets and validation datasets. To configure the model in the best way, a hybrid gravitational search algorithm-artificial neural network (GSA-ANN) was also developed in this study. The findings confirmed ANN as an effective alternative for measuring the ultimate PD of cementitious pastes. ANN provided high levels of accuracy, practicality, and effectiveness in the process of predicting the PD value. Based on the final results, the implementation of the hybrid GSA-ANN technique causes a significant decrease in the number of tests conducted on experimental samples, which results in not only saving time and money, but also reducing the CO2 emission volume.
Polyethylene terephthalate (PET) fiber is a green-friendly fiber that is capable of enhancing the mechanical properties of wet-mixing shotcrete. The main purpose of this study is to see how varied volumes of waste plastic fibers (WPF) affect the flowability and mechanical properties of wet-mix shotcrete. For this aim, a variety of experimental tests based on WPF content were chosen. Fresh and mechanical tests included slump, T500, density, compressive strength, and splitting strength were applied. The results shown a improved in shotcrete performance as the WPF content increased. Among all fitting correlations, density and compressive strength revealed the strongest linear ship association. Due to greater interlocking between WPF and concrete matrix, WPF was a major use in enhancing splitting tensile strength. WPF had the most influence on splitting strength, with 23–31 percent, 7–23 percent, and 6–38 percent for 7, 14, and 28-day, respectively.
This main aim of this study is evaluate wide range of fresh and hardened properties of sustainable self-compacting concrete containing various types of Cement Replacement Materials with optimum contents of Polyethylene Terephthalate PET waste plastic as fibers and fine aggregate replacement. This is to evaluate effect of the two forms of PET and to determine the best CRMs could be used with sustainable SCC. such as limestone, glass powder and fly ash with high replacement rate of 70% by weight of cement were used while fourth one (kaolin) was used with replacement rate of 20%. PET fibers were added to SCC with an aspect ratio of 24.4 and 0.7% volume fraction whereas fine aggregate partially replaced by 4% of waste plastic. Four reference mixtures contained FA, LP, GP and KA only, same four mixtures contained 0.7% PET fibers by volume, and the other same four mixtures contained 4% PET fine aggregate by volume. The obtained results all tested fresh properties, which include slump flow, T500, L-Box and segregation resistance were within the limits of the specification reported in EFNERC guidelines. Further, the forms PET have an adverse effect fresh properties of SCC. As for hardened properties (compressive strength, splitting tensile strength, flexural strength and impact strength). Further, this produced type of SCC showed an range of compressive strength (15.2-31.64 MPa) at 28 days. It can be from the current study the best CRMs to be used in SCC containing PET wastes was FA in terms of most tested properties.