This study investigated the effect of adding the plastic waste resulting from cutting the bottles by hand as fibers in the concrete mixture with long of (3cm) and width of (0.3cm) with and without using of silica fume (SF) with (5 and 10)% of cement weight. Fibers of plastic waste added as a percentage of concrete volume. These percentages were (0.5 and 1)%. Reference concrete mix was also made for comparative purposes. Mechanical properties were tested included compressive and splitting tensile strength. Results showed that, there was an increasing in splitting tensile strength of the mixes containing plastic fibers with (SF) (5)% more mixes included plastic fiber with (SF) equal to 1% of cement weight. At 28 days according to reference concrete , the increasing percentages were (9%, 17.67%) for (0.5%,1%) plastic fibers. (8%, 15%) for plastic fibers with (SF) equal to (5%) and (5%, 3.34%) for plastic fibers with (10%) (SF). There were a decreasing in compressive strength for mixes containing plastic fibers and this decreasing increased with the percentage of plastic fibers. According to the reference concrete the decreasing values of compressive strength at (28 days) were (9.82%, 22.12%) for (0.5%, 1%) plastic fibers, (5.72%, 17.08%) for (0.5%, 1%) plastic fibers with (5%) (SF) and (6.78%, 19.04%) for plastic fibers (0.5%, 1%) with (SF) (10%) respectively.
An experimental investigation has been carried out to evaluate the effectiveness of Polyvinyl chloride (PVC) confinements in short plain circular concrete columns. The experimental part is conducted using different tube diameters (110, 160, 220, and 250 mm) with two types of confinement strategies (fully and confined with the cut ends). The results are validated with unconfined samples (control samples). The test results showed that using external confinement of concrete columns by PVC tubes enhances the ultimate load capacity of the short columns. For fully confined samples, the enhancement ratio ranges between 5% and 8.3%, and from 4.16% to 15% for samples with cut ends. Furthermore, the confining of PVC pipes with the cut ends has a more considerable effect on load capacity for all diameters except the ones with 250 mm, where the samples with full confinement ( carried a bigger load than those with cutting ends. Finally, a numerical simulation of samples is carried out by the finite element model using the software. For all scenarios, the results of the numerical analysis showed considerable similarity to the experimental results, with of 0.95 indicating the high linearity between the actual and simulated compressive strength values. Moreover, the induces fewer simulated errors with a relative error ranging from 0.16% to 6% for all scenarios.
Concrete is a ubiquitous construction material used globally to build bridges, homes, hospitals, schools and sewage systems. Concrete used in sewage systems is exposed to an aggressive environment, like elevated temperature and humid conditions, in addition to aggressive sulphate. The combined effect of these conditions results in the premature deterioration of structures. This study was investigated the effect of replacing cement by fly ash (FA) in cement mortar by different ratios and a quarry dust as sand. The reference mortar mix grade was (35 MPa) and the other mixes were with various percentages of FA (5%, 10%, 15%, 20%, 25%, 30%, and 35%) by weight of cement. This study evaluated the effect upon the compressive strength, splitting tensile strength, fracture strength, and modulus of elasticity of mortar containing FA exposed to the magnesium sulphate (MgSO4) with concentration 30000 mg/l. Mixes were created using varying ratios of FA to identify the optimal concentration; these were compared against normal concrete. At replacement ratios of 20% at all ages, optimum compressive strength, splitting strength, fracture strength, and elastic modulus were obtained. Conversely, mixes with replacement ratios greater than 20% produced less strength than the control mix (without FA). The FA mortar's strength remained higher than that of regular mortar exposed to the same conditions of magnesium sulphate after 28 days, despite a reduction in compressive strength. As result, the replacing some of the cement in the concrete mix, particularly in the ratio of 20%, with FA, the concrete can be formed that is more resistant and more capable to withstand MgSO3 attack.
This article aims to study the mechanical properties of concrete containing the recycled and crushed aggregate instead of normal aggregate separately, and reinforced with volumetric ratios equal to (0.25,0.5,0.75,1,1.25 and 1.5)% of plastic fibers, which produced by cutting the plastic water bottles as a partial replacement from volume of coarse aggregate. Preliminary results showed that the compressive strength of recycled aggregate concrete(RAC) increased with increasing the waste plastic fibers (PET) more than the observed values of crushed aggregate concrete(CAC), while the results showed that the splitting tensile strength of concrete samples containing recycled aggregate have a higher splitting tensile strength than those containing the crushed aggregate. On the other hand, it was noted that the increasing in the proportions of PET from (0.25-1) % showed an increase in compressive and splitting tensile strength, but after the ratio of PET used equal to (1% ), it was observed a decreasing in both of compressive and splitting tensile strength.
According to the growing of the world's population, the necessitate for using different building materials such as cement, steel, admixtures, wood and aluminium increased. The main problem faces the world with the increasing need for building materials is the construction wastes, which are a type of environmental pollution that must be reduced. This study focused on aluminium and iron wastes resulted from factories and the possibility to reuse these wastes again like partial replacement from sand with proportions (0.25, 0.5, 0.75 and 1%) in concrete mixtures for both types of residues at ages (7, 14, and 28) days. It had studied the effect of the using of aluminium residues (AR) and iron residues (IR) especially on the mechanical characteristics of concrete. These mechanical characteristics were the compression strength (CS) and tensile strength (TS). The achieved results were compared between the residues concrete specimens and those of reference concrete. Also, the effect of age and replacement percentage for samples which they contain AR and IR had been discussed. The results had shown that the (CS) of iron residues concrete samples (IRC) was increasing with increasing of the iron residues percentage till (0.5%) (IR) in opposite of the observed values of aluminium residues concrete (ARC), as well as for the results of the (TS) of concrete samples which containing the mineral residues at all ages. Where it was observed that the using of aluminium residues (AR) showed a decreasing in the values of (TS) and (CS) compare with reference concrete, but with the use of iron residues (IR) both of (TS) and (CS) results were more than their counterparts of reference concrete at all ages for the first two percentages of replacement.
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