Shred Size Research Articles

Evaluation of Compression Behaviors of Marine Clay Reinforced with Waste Shredded Tires

This study evaluates the compression behaviors of a soft marine clay reinforced with waste shredded tire (WST) at different sizes (<0.5 mm, 0.5–2.0 mm, and 2.0–4.0 mm) and contents (15%, 35%, and 50%). Results from compression tests indicate that the compression index (Cc) of WST‐reinforced soft clay decreases with increasing WST shred size and content. The swelling index (Cs) increases as the WST shred size and content increase. The difference in compression curves becomes more significant for composite reinforced at large shred size. The void indexes of WST‐reinforced Lianyungang clay can be well normalized regardless of WST shred size and content by a regression line. The WST dominates the compression behavior of the WST‐clay composite, as the WST would be compressed prior to the clay particles. The results in this study provide an optimum WST content at 50% with shred size of 2.0–4.0 mm for reinforcing the Lianyungang marine clay for achieving higher compressibility, contributing to the input database of machine learning for WST‐reinforced soil.

Pullout Response of Uniaxial Geogrid in Tire Shred–Sand Mixtures

Use of tire shred–soil mixtures as backfill materials in mechanically stabilized earth walls has several advantages over other backfill materials: (1) good drainage, (2) high shear strength, and (3) low compacted unit weight. This paper presents the results of laboratory pullout tests performed on uniaxial geogrid embedded in tire shred–sand mixtures. The effects of tire shred size, tire shred–sand mixing ratio and confining pressure on the interaction between the geogrid and tire shred–sand mixtures are evaluated. Three sizes of tire shreds are considered: tire chips (with 9.5 mm nominal size), tire shreds 50-to-100 mm long and tire shreds 100-to-200 mm in length, with mixing ratios of 0, 12, 25 and 100 % of tire shreds in the mixtures (by weight). Based on compaction testing of a number of mixtures, the optimal mixing proportion of tire shreds and sand was found to lie between 25/75 and 30/70 (by weight of tire shred and sand); this is equivalent to approximately 40/60 and 50/50, respectively, by volume of tire shreds and sand. The pullout resistance of a geogrid embedded in tire shred–sand mixtures is significantly higher than that of the same geogrid embedded in tire shreds only. The size of the tire shreds has negligible effect on the pullout resistance of a geogrid embedded in mixtures prepared with either low (12/88 mix) or high (100/0 mix) tire shred content. However, when the 25/75 mixture is used, greater geogrid pullout resistance was obtained for the geogrid embedded in tire chip–sand mixtures than in tire shred–sand mixtures.

Physical properties of pizza Mozzarella cheese manufactured under different cheese-making conditions

The effect of manufacturing factors on the shreddability and meltability of pizza Mozzarella cheese was studied. Four experimental cheeses were produced with 2 concentrations of denatured whey protein added to milk (0 or 0.25%) and 2 renneting pH values (6.4 or 6.5). The cheeses were aged 8, 22, or 36d before testing. Shreddability was assessed by the presence of fines, size of the shreds, and adhesion to the blade after shredding at 4, 13, or 22°C. A semi-empirical method was developed to measure the matting behavior of shreds by simulating industrial bulk packaging. Rheological measurements were performed on cheeses with and without a premelting treatment to assess melt and postmelt cheese physical properties. Lowering the pH of milk at renneting and aging the cheeses generally decreased the fines production during shredding. Adding whey protein to the cheeses also altered the fines production, but the effect varied depending on the renneting and aging conditions. The shred size distribution, adhesion to the blade, and matting behavior of the cheeses were adversely affected by increased temperature at shredding. The melting profiles obtained by rheological measurements showed that better meltability can be achieved by lowering the pH of milk at renneting or aging the cheese. The premelted cheeses were found to be softer at low temperatures (<40°C) and harder at high temperatures (>50°C) compared with the cheeses that had not undergone the premelting treatment. Understanding and controlling milk standardization, curd acidification, and cheese aging are essential for the production of Mozzarella cheese with desirable shreddability and meltability.

Fracture properties of concrete with waste compact disc shred

A large amount of electronic waste like computer compact discs (CDs) is being generated every year and their disposal has become a major environmental concern that needs to be addressed wisely. Therefore now, the addition of recycled materials into concrete is increasingly attracting the attention of civil engineers worldwide. However, adding computer compact disc (CD) shreds into concrete has not been examined. In this research, the fracture behaviour of concrete containing waste CD shreds was investigated using the three point bending notched beam test, according to RILEM recommendations. The main parameters studied include CD the content and size of shreds. The study indicates that the fracture energy and modified characteristic length were found to increase significantly with the increasing proportion and size of CD shreds due to anchoring and bridging effects. In other words, concrete with higher amounts and larger sizes of CD shreds exhibit higher cracking resistance and the brittleness decreases accordingly.

Determination of Optimal Surface Area to Volume Raio for Thin-Layer Drying of Breadfruit (Artocarpus altilis)

Experiments to determine the optimal size shred of breadfruit for sun drying in the Caribbean were conducted and verified. To determine optimal shred size, ease of shredding and handling as well as the drying characteristics were considered. Additional experiments compared the drying characteristics of breadfruit to several types of produce more readily available for use in the laboratory and examined the effect of alternative bases or backgrounds for sun drying. An optimal surface area to volume ratio is recommended and found to dry breadfruit under average Caribbean conditions (27-30 ˚C, 60-65% RH, ~800 W/m2 solar radiation and 1.5-2.0 m/s prevailing winds) in about three hours.

Hydraulic conductivity of tyres in landfill drainage systems

Whole or shredded scrap tyres are sometimes proposed as an alternative to conventional aggregates in landfill drainage systems. Landfill basal drainage systems are, however, subjected to large overburden stresses from the overlying waste, which may compress a tyre drainage layer, thereby reducing its porosity and hence its effectiveness. Previous work has indicated that tyre drainage layers will remain effective under high stresses, but tests have in the main been restricted to small (&lt;100 mm) shred sizes. The use of coarser shreds or even whole tyres for landfill drainage systems may be advantageous as they are more economical to produce and may be less prone to clogging than smaller shreds. In the current paper, the results of large-scale (2 m diameter) tests to investigate the variation in hydraulic conductivity (permeability) with stress of 50, 200 and 450 mm nominal size tyre shreds are compared with data from the literature for smaller-size shreds and whole tyres. Tests were carried out at vertical stresses up to 600 kPa, representing landfill depths of up to about 60 m. Potential errors in laboratory test procedures are highlighted and the influence of scale and the relative test chamber to particle size on the results is discussed. It is concluded that a chamber to particle size ratio of at least 6 is needed with a rigid walled permeameter, if errors owing to peripheral flow effects are to be avoided. Relationships between shred size and drainage properties are investigated: no clear correlation between tyre shred size and drainage properties in the particle size range 50–450 mm is found. Whole tyres, however, generally have a slightly higher hydraulic conductivity, while samples containing a significant proportion of material less than 20 mm in size have generally a lower hydraulic conductivity at a given vertical stress than clean samples of larger shreds.

Physical and Chemical Properties of Recycled Tire Shreds for Use in Construction

The purpose of this study was to determine the physical and chemical properties of tire shreds for use in engineering construction as a replacement for aggregates in embankments or as backfill. In general, test results revealed that tire shreds can be utilized in construction applications. As the size of tire shreds increases, physical properties such as specific gravity remained constant at 1.06–1.1. Gradation of tire shreds was also tested, and the results were comparable to other researchers (i.e., ranging from 50 to 300 mm). As the tire shred size increased, the hydraulic conductivity increased from 0.2 to 0.85 cm/s. Increasing the compaction energy had little effect on the final compaction density. The angle of friction and cohesion ranged from 15 to 32° and 349 to 394 N/m², respectively. As the particle size (from 50 to 300 mm) of the tire shreds increased, the shear strength of the scrap tire increased. Moreover, as the tire shred size increased, compressibility increased. Chemical analysis of tire shreds was conducted to illustrate how properties such as total organic carbon (TOC), pH, and turbidity change with tire size. As tire shred size increases, the results illustrated a decrease in TOC (from 22.7 to 3.1 ppm) and turbidity (from 254 to 99 NTU). Continuous flow column tests were conducted on tire shreds and showed improved water quality (TOC, turbidity, and iron) with time. However, pause flow column tests showed reduced water quality, which implies that placement of a tire embankment below the water table where ponding can occur may reduced water quality. TGA tests were also conducted to determine the thermal stability of tire shreds. In general, tire shreds are stable up to temperatures of 200°C. This indicates that other mechanisms may be attributed to the exothermic reactions, which occurred in tire fills.

Shear Strength of Large-Size Shredded Scrap Tires

One application for recycling large (1.4-m top size) shredded tires is as an intermittent stream or ravine crossing in place of a culvert. To measure the shear strength of large-size shredded scrap tires for use in slope stability analyses, a large-scale direct shear box (0.91 0.91 m in plan) was constructed. Two failure criteria were used, yielding similar results. A friction angle of 37° and a cohesion intercept of 3.1 kPa were obtained for large shear displacements, and the same friction angle of 37° and a zero cohesion intercept were interpreted using the 10 percent displacement failure criterion as defined by AASHTO. When shear-strength data on shredded tires from this and previous studies are analyzed, there is no apparent relationship between shred size and strength. The shear strength of the combined data, however, are well represented by the power function τ = 1.68σ0.74, where both τ and σ are in kPa. It is suggested that this nonlinear relationship, independent of shred size, can be used in stability analyses where the shear strength of shredded tires is needed.

ＰＥＴとＰＶＣの風力分離について

The air separation of PET and PVC was carried out by taking advantage of the different crushing resistance of two plastics. PET bottles and a sheet of PVC (0.5 mm in thickness) were shredded to small square pieces (5 mm × 5 mm). Both shreds were treated with a shear-type crusher. The PET shreds were bent and twisted by the crush so that they were blown up easily, but the PVC shreds were not. After the crushing for 90 sec, 100 % of the PET shreds were blown up at the air flow rate of 3 m/sec whereas the PVC shreds were not. The increase in initial shred size of PET up to 14 mm × 14 mm resulted in increasing the yield of PET at low air flow rate.

たばこ刻の加熱乾燥諸条件が膨こう性に与える効果

The detailed fundamental experiments about heat drying of tobacco shreds were carried out in order to obtain the effect of heat drying condition on the filling capacity of tobacco shreds which were heated in the dryer used in the process of the cigarettes manufacturing industry. The variables of heat drying condition chosen were the temperature of heated wall (80-240°C), the temperature of heated air (40-190°C), the drying time (7-360sec), the moisture content of the shreds before drying (14-22% WB), their specific volume (1.5-13.0cc/g) and their size determined by sieving (1-4mm) etc. The varieties of tobacco used were the flue-cured and the domestic. The important results obtained are as follows:(1) When the wall temperature and the air temperature became higher, and when the drying time was longer, the filling capacity of tobacco shreds increased.(2) In order to increase the filling capacity of shreds, the drying with heated wall was more effective than that with heated air.(3) By means of an analysis of multiple regression formula among the filling capacity and other parameters representing the magnitude of thermal effects on tobacco, (that is, the temperature of tobacco shreds and their moisture content at the last moment of drying), it was clear that the influence of shreds temperature on filling capacity was greater than that of the moisture content of shreds.(4) The effects of both moisture content and specific volume of shreds before drying on filling capacity were smaller than that of the wall temperature. The tendency of variation of filling capacity with the change of size of shreds in the flue-cured variety differed from that in the domestic variety.