Loose-fill Materials Research Articles

Practical Use of Materials of Natural Origin as Loose-Fill Insulations in Open-Diffusion Constructions—Observation and Numerical Simulation

The increasing requirements concerning the consideration of the environmental impact of building materials, along with the simultaneous preservation and enhancement of building thermal parameters, have led to a surge in interest in insulations based on organic or recycled materials. Despite the growing interest in these materials, there remains a scarcity of scientific studies regarding their hygrothermal properties. Within the scope of the research described in the text, the insulation properties of loose-fill materials (hemp shives, cellulose fibers, loose wood wool, and mineral wool as a reference) in wooden frame walls were analyzed. The authors simulated walls with the same U value filled with these materials using Delphin 6.1 software. The simulation time was 3 years, considering the appropriate climatic conditions of Olsztyn and different microclimatic conditions inside the rooms. Insulations made of natural organic can absorb and reveal moisture to the internal environment, while mineral wool transports the moisture to the outside, which may cause condensation problems. Insulations made of hemp shives or wood wool do not increase the level of accumulated moisture over time, which results in thermal stability. In contrast, cellulose and mineral wool store more moisture, which in wet conditions increases the heat flux by 6.9% and 5.2%, respectively.

Numerical investigation of jacking method for asymmetric settlement rectification in tilted concrete buildings

In the town of Fereshteh, Tabriz, Iran, there is a growing concern regarding the tilting of recently constructed buildings. This uneven settlement issue can be primarily attributed to variations in loose fill material thickness, elevated groundwater levels, and the presence of loose sandy layers intermixed with clayey layers. The challenges posed by these tilted structures are further compounded when dealing with historically significant buildings, making demolition an undesirable and wasteful solution. Therefore, alternative restoration methods must be explored. This study focuses on the application of the jacking technique to rectify the tilt observed in reinforced concrete buildings ranging from four to eight stories in height. To simulate the rectification process, numerical modeling using the finite element method was employed. The strategic placement of jacks was critical, as they applied force until the foundation achieved equal vertical displacement on both sides or until the uneven settlement was reduced to an acceptable level. Ensuring the structural integrity of the building during this rectification process was of paramount importance to prevent cracking or collapse due to the forces exerted by the jacks. Elements on the first floor experienced significantly higher internal forces compared to their counterparts on upper floors. Stress concentration was notably observed at the intersection point of the columns and the foundation surface. This highlights the critical importance of positioning the jacks directly beneath the axis of the columns or bearing elements to ensure effective rectification. Based on the results obtained for the studied structures, it becomes evident that employing the jacking method becomes unfeasible when a section of the raft experiences a settlement exceeding 10 cm. This is due to the drastic change in stress distribution conditions within the structural components under such circumstances. However, the jacking method remains a viable and effective solution for settlements below this threshold, rectifying uneven structural settlements without causing harm to the structural elements.

Morphological, physical, thermal, and mechanical properties with the aspect ratio effects of bio loose-fill packaging from corn stalk

Protective packaging, such as loose-fill material, is commonly used for void filling in packages during transportation and handling. Due to environment concerns about packaging materials, alternative materials derived from agricultural residues, such as corn stalks (CS), are of attention. Dried internodal CS without rind (DCS-R) were prepared as a cylindrical-shaped bio loose-fill packaging pieces (DCS-RP) at three different aspect ratios [length/diameter (L/D) of 0.4, 0.8, and 1.2]. The morphological, physical, and thermal properties of the DCS-RP were investigated and the effect of the L/D ratio of the DCS-RP was examined under compression loading. The DCS-RP exhibited a porous structure with a low density and bulk density, while the packing efficiency at all L/D ratios was less than 1. Different compressive resistance and failure patterns of the DCS-RP were obtained, depending on the direction of compression loading (parallel and perpendicular) to the DCS-RP. In addition, the L/D ratio of bulk DCS-RP also affected the compressive resistance. The results of this study provide important information for future investigations on the protective ability of DCS-RP to the products inside the packages during transportation and handling.

Potential of some Latvian Industrial Crops Residuals for Conversion to Bio-Based Thermal Insulation Material

Some industrial crops residuals like wheat straw, buckwheat husks and reeds were used in the study as raw lignocellulosic materials to evaluate their potential as thermal insulation material. Steam explosion (SE) pre-treatment was used to disrupt and convert the raw material smooth shape to foamy fibrous shape. Two level Factorial design was used to evaluate the impact of raw material fraction size (10-20-30 mm), moisture content (10-30-50%), SE temperature (200-215-230 °C) and duration (00-30-60 s) on bulk density and thermal conductivity of the obtained loose-fill materials. The results show that all selected raw materials could be characterized as thermal insulation materials as the determined thermal conductivity was in the range of 0.042–0.058 W (m K)-1 including neat samples. In spite of effective fibrillation of raw materials SE pre-treatment did not improve their thermal conductivity. The determined bulk density of loose-fill crops varied in range of 23–184 kg m-3 depending on all variables; the SE pre-treatment showed the most significant effect on its reduction. Based on the study results the most suitable crops residues for bio-based thermal insulation purposes are suggested wheat straw and reeds demonstrating the lowest values of bulk density and thermal conductivity.

Full-Scale Field Test on Construction Mechanical Behaviors of Retaining Structure Enhanced with Soil Nails and Prestressed Anchors

Soil nailing combined with prestressed anchors has a good workability and is relatively cheap in constraining the horizontal displacement. Current research on the technique, whether theoretical analyses, numerical simulations, or model tests, was conducted under ideal working conditions. However, in fact, external disturbances, such as tensioning-lagging of the anchor, are very common and play an important role on stress and displacement. Therefore, it is of great significance to carry out a field test considering the effects of external disturbances, which can obtain real and reliable data through real-time monitoring. In this paper, the impacts of the construction conditions on practical engineering are discussed based on in situ tests, and some reasonable suggestions for the upgrading of misbehaviors in the current construction situation are put forward. In particular, the influence features of soil predisturbance, excessive excavation, unloading on the surface of edges, tensioning-lagging of the anchor, and continuous rainfall on the stress–time curve of soil nails under practical working conditions are analyzed. Behaviors of three different retaining structures enhanced with (i) soil nails; (ii) soil nails and prestressed anchors without unbonded parts; and (iii) soil nails and prestressed anchors with a 2.5 m unbonded part were monitored during staged excavation to investigate the influences of (i) the prestressing force and (ii) the unbonded part of the prestressed anchors on the performance of the entire retaining system. Results show that (i) the prestressing force is the main factor affecting the stress and deformation of the composite retaining system, which is consistent with the existing literature; (ii) the variation of the magnitude and distribution of the soil nail force responding to the anchor prestressing force, however, showed no systematic trend; and (iii) the unbonded part of anchors, which was validated to be the main factor affecting the structural stability in dense materials in the existing literature, is found to have a minor influence in loose fill materials used in this study.

Assessment of mussel shells building solutions: A real-scale application

The construction sector is a key generator of greenhouse emissions, so the use of alternative low-emission building materials is a growing tendency. This work describes and analyses an innovative sustainable building that includes mussel shells in all its constructive elements. This material is a by-product of the canning industry that is nowadays landfilled. Mussel shells were used as aggregate in the concrete strip footing (foundation) and in the exterior and interior coating mortars (walls), and as loose-fill material for the whole envelope insulation (floor, walls, and roof). The results from both the laboratory and the constructive process were useful to improve the solutions and to develop a building with low energy consumption. Finally, the energy demand of the building was assessed using the Passive House Planning Package (PHPP) software and the blower door test was carried out to measured air tightness. It can be concluded that mussel shell materials meet the requirements of Passive House standard for energy efficient buildings: simulation results showed a primary energy consumption of 86 kWh/(m2yr), that is a 28.3% lower than the value fixed by the standard.

TIPP—Safety Tips for Home Playground Equipment

Patient Education| 2021 TIPP—Safety Tips for Home Playground Equipment Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation TIPP—Safety Tips for Home Playground Equipment. Pediatric Patient Education 2021; 10.1542/peo_document334 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search nav search search input Search input auto suggest search filter All AAP SitesAll PublicationsPediatric Patient Education Search Advanced Search Subjects: TIPP - The Injury Prevention Program Topics: playgrounds When purchasing home playground equipment, choose a set that is labeled as meeting safety standard ASTM F1148.Carefully supervise young children using playground equipment. Keep children from shoving, pushing, or fighting.The surface under playground equipment should be energy absorbent. Use safety-tested mats or loose-fill materials (such as shredded rubber, sand, wood chips, or bark) maintained to a depth of at least 9 inches.Install the protective surface at least 6 feet (more for swings and slides) in all directions from the equipment.Swing seats should be made of something soft, not wood or metal.Children should not twist swings, swing empty seats, or walk in front of moving swings.Put home playground equipment together correctly. It should sit on a level surface and be anchored firmly to the ground. You may need help from a professional to install the equipment... © 2020 American Academy of Pediatrics. All rights reserved. You do not currently have access to this content.

Research of Wood Waste as a Potential Filler for Loose-Fill Building Insulation: Appropriate Selection and Incorporation into Polyurethane Biocomposite Foams.

Currently, the recycling potential of wood waste (WW) is still limited, and in a resource efficiency approach, recycling WW in insulation materials, such as polyurethane (PUR), appears as an appropriate solution. It is known that the quality of WW is the main aspect which influences the stability of the final products. Therefore, the current study analyses different WW-based fillers as possible modifiers for polyurethane biocomposite foams for the application as loose-fill materials in building envelopes. During the study of WW-based fillers, it was determined that the most promising filler is wood scobs (WS) with a thermal conductivity of 0.0496 W/m·K, short-term water absorption by partial immersion—12.5 kg/m2, water vapour resistance—0.34 m2·h·Pa/mg and water vapour diffusion resistance factor—2.4. In order to evaluate the WS performance as a filler in PUR biocomposite foams, different ratios of PUR binder and WS filler (PURb/WS) were selected. It was found that a 0.40 PURb/WS ratio is insufficient for the appropriate wetting of WS filler while a 0.70 PURb/WS ratio produced PUR biocomposite foams with the most suitable performance: thermal conductivity reduced from 0.0523 to 0.0476 W/m·K, water absorption—from 5.6 to 1.3 kg/m2, while the compressive strength increased from 142 to 272 kPa and the tensile strength increased from 44 to 272 kPa.

Mussel shells: A canning industry by-product converted into a bio-based insulation material

The canning industry in Galicia produces 25 thousand tonnes of mussel by-product (i.e. unconsumed shells) per year, having a significant environmental impact. Mussel shell becomes suitable for different uses after undergoing heat treatment such as poultry feed or bedding, etc. However, other end uses for this by-product must still be explored. Building insulation material (for instance expanded polystyrene, extruded polystyrene, polyurethane, etc.) has a significant harmful effect on the environment, which is especially seen when analysing its entire life cycle (use of large amounts of energy and water for production, difficulty recycling or reusing waste in the event of demolition or refurbishment, etc.). The aim of this research is to prove the feasibility of using mussel shell as a building solution. Mussel shell has been found to have thermal and acoustic characteristics suitable for using it as building insulation material. Mussel shell confined inside an enclosed space (e.g. a wooden box) has a thermal conductivity similar to that of a light conifer wood, so it can be considered a material with low thermal conductivity. Furthermore, several acoustic studies indicate that a section of confined mussel shell displays a behaviour similar to that of commercialised insulation material. The embodied energy of mussel shell as a loose-fill material is similar to that of other bio-based insulation materials. The main goal of this paper is to demonstrate that it is possible to design mussel shells building solutions, that actively participate in environmentally responsive architecture.

Properties of potato flour-based loose-fill foams

Abstract Potato flour-based foams were made as loose-fill packaging materials. The different potato flour moisture contents of 10 to 16% (dry basis) were used and extruded using a single screw extruder. The water was employed as a blowing agent in this work. The water solubility index (WSI), compressive strength, foam appearance, expansion ratio and foam cell structure were evaluated. WSI of foams ranged between 48 and 67%. Increasing the moisture contents of potato flour tended to increase rigidity and irregular surfaces of foams. However, the expansion ratio and cell size of foams decreased as the moisture contents of potato flour increased.

The selecting of building insulation material by the analytic hierarchy process

Today one of the Federal programs implemented in Russia at the state level, is a program of energy conservation and energy efficiency to reduce the specific consumption of fuel and energy resources. In developed countries, private landlords are using almost 30% of all generated power, i.e. almost as much as industry and more than all transport combined. About 80% of the energy consumed goes to space heating, but much of it is often wasted due to a mismatch of home insulation with the adopted standards. Thus, a rational choice of insulating material is one of the most important tasks to reduce heat losses in residential buildings. There is a wide variety of building insulation materials available for purchase. For heat insulation of external walls of residential buildings are most often used single-piece insulation materials – batts, blankets, panels. Their essential advantage in comparison with loose-fill materials, such as crushed expanded polystyrene, expanded vermiculite, claydite, are the simplicity and speed of installation, acceleration of construction works and improvement of their quality. Autoclaved aerated concrete blocks are used traditional for thermal walls insulation, they does not rot, does not burn, does not emit toxic substances during operation, has an average water vapor permeability and, therefore, well regulates the humidity in the room. However, the masonry of aerated concrete blocks has a significant disadvantage – a large average density. Alternatively, the modern industry offers a wide range of synthetic insulating materials, the most popular are fiberglass, mineral (rock or slag) wool, plastic or natural fibers, polystyrene, polyisocyanurate, polyurethane foam boards. As well become increasingly popular natural materials such as cellulose, peat blocks, cork, fiberboard, insulation from flax or hemp fibers. All of these materials have their advantages and disadvantages, so the task of choosing the optimal variant is complex and requires special methods to eliminate the subjectivity of evaluation. The article describes the approach to selecting the best option of building insulation material from the available options by the set of its quantitative and qualitative characteristics. It is proposed to carry out the evaluation of options and selection of the best option based on the analytic hierarchy process. The article presents the results of the selection of the most appropriate thermal insulation material for residential buildings.

Loose Fill Material from Hemp Shives and Binding Material for Thermal Insulation and Structural Use

Currently building sector requires the use of new technologies and innovative materials. Realization of mentioned requirements allow ensuring rate of performed works, reducing labour building constructions costs and improving building performance. In current work, loose fill material from hemp shives and binding material are analysed. The mixture of hemp shives and binder may be used in frame constructions as blown or poured loose fill material for thermal insulation or structural use. Hardened composite is characterized by high strength and excellent thermal conductivity when it is used in building partitions and enclosures. In our work hemp shives are mineralized with different amount of liquid sodium silicate and mixed with cementitious binder. Macro-and microstructures of hardened composite are analysed, influence of amount of mineralizer on the strength and thermal conductivity of composite is evaluated.

Steady-state thermal measurement of moist granular earthen materials

A technique based on the heat flow meter method is proposed for measuring the thermal conductivity of moist earthen and granular loose-fill materials. Although transient methods have become popular, this steady-state approach offers an uncertainty that can be reliably estimated and a test method that is widely accepted for building certification purposes. Variations to the standard method are proposed, including the use of a rigid holding frame with stiff base and silicone sponge buffer sheets, in conjunction with difference measurement to factor out the contributions from base, buffers and contact resistance. Using this approach, results are presented for green-roof substrates based on scoria, terracotta and furnace-ash at different moisture contents. Thermal conductivity ranged from 0.13 to 0.80 W/m K and fitted well to linear regression plots against moisture content. Further comparative measurements of a single specimen showed that direct measurement was less consistent than difference measurement and thus indicated that thermal resistance was higher by 0.023 m2 K/W, attributable to the presence of contact resistance.

Numerical modelling of soil nails in loose fill slope under surcharge loading

A plane–strain numerical model has been developed to mimic a nailed loose fill slope under surcharge loading. The model has been used to back-analyse a field test that was conducted to examine the behaviour of soil nails in loose fill slopes under surcharge loading. Incremental elasto-plastic analyses coupled with pore water diffusion have been performed to study the internal deformation, water content redistribution in the soil, and the performance of the soil nails during and after the application of surcharge loading. The model parameters describing the mechanical and hydraulic properties of the nailed slope were obtained from field or laboratory tests. Different modelling techniques and boundary conditions for mimicking soil–nail interaction in loose fill material have been examined. Comparisons between numerical predictions and field measurements demonstrate that a new interfacial model, denoted as the embedded bond–slip interface model, is more suitable for mimicking the interfacial behaviour. Despite the simplicity of the numerical model, the predicted responses are in close agreement with the field test results, in particular the mobilisation and distribution of nail forces in response to surcharge loading. Both the numerical and the field test results suggest that soil nails are capable of increasing the overall stability of a loose fill slope for the loading conditions considered in this study. The increase in confining stress along the soil nails near the surcharge area is central to the overall stabilising mechanism. On the contrary, the nail forces mobilised near the nail heads are much smaller, indicating that the beneficial effect of having a structural grillage system at the slope face is limited for the range of surcharge pressures considered in this study.

Soil–Nail Pullout Interaction in Loose Fill Materials

A laboratory study was conducted to investigate the behavior of soil nails embedded in loosely compacted sandy fills. By varying the overburden pressure, the peak pullout force and the load–displacement behavior were determined by carrying out pullout tests in a displacement-rate controlled manner. The test results were compared to other published ones. The present results show that the pullout resistance can be interpreted with conventional soil parameters. The effect of retrained dilatancy, which is considered to be the reason for high pullout resistance in dense materials, is negligible in loose fill materials except under very low stress level. Furthermore, pullout resistance increases with overburden pressure opposed to some field test results reported in the literature which show no systematic trend in pullout resistance with overburden pressure. A numerical model was developed to simulate the mobilization of pullout force in soil nails. It has been shown that a simple one-dimensional spring model can be used to simulate the pullout load–displacement relationship.

Comparison of Conventional Extraction Under Reflux Conditions and Microwave-Assisted Extraction of Oil from Popcorn

Popcorn offers an environmentally friendly alternative to the commercial synthetic loose-fill packing materials. Popcorn could be used for cushioning purposes if the oil is extracted after the popping process. Conventional and microwave-assisted extraction methods were used for oil extraction from whole and ground, popped and unpopped kernels. Conventional extraction method achieved 68.5% oil recovery from whole popped kernels. Whole unpopped kernels were not efficiently de-oiled with either of the methods. It is recommended to extract the oil from popped kernels; corn varieties with higher starch content and lower oil content should be used.

Assessment of the performance of organic and mineral-based insulation products used in exterior walls and attics in dwellings

The assessment of the performance of organic and mineral-based insulation products used in exterior walls and attics in traditional Danish housing estate was evaluated. The assessment covered the ability of the materials to be handled on site as well as measurements of the performance of the materials once installed and exposed to normal use of the dwellings and Danish weather conditions over a 2-year period. Evaluations were based on, on-site observations, thermographic observations and measurements of temperature and moisture conditions within the different materials used. Eight different products were used for thermal insulation including six organic and two mineral fibre materials. Loose-fill material and predefined fixed-shape products were used. The eight different products were installed in 16 dwellings, two neighbouring dwellings were insulated with each product. Exterior walls were constructed without PE vapour barriers while ceilings were constructed with PE vapour barriers.

Methods of Expanding Polystyrene to Ultra Low-density Foam

Ultra low-density expanded polystyrene is obtained by an optimum formulation or by extended exposure to atmospheric steam. A polystyrene resin is rheologically modified to have both ease of flow and resistance against collapse. The collapse resistance is imparted either by light crosslinking of the resin with a silane compound or by adding a small amount of polyphenylene ether. Extended exposure to steam permits continuous extension of cell walls by reducing orientation. An expanded polystyrene loose fill material having an expansion ratio exceeding 200 has been achieved.

Laboratory study of soil–nail interaction in loose, completely decomposed granite

The technique of soil nailing is seldom used in stabilizing loose fill slopes because there is a lack of understanding of the interaction behaviour of nails in loose fills. A large-scale laboratory apparatus has been built to study the soil–nail interaction in loose fill materials. Pullout tests were performed in a displacement-rate-controlled manner on steel bars embedded in loose, completely decomposed granitic soils. The load–displacement curves have distinct peak values followed by a sharp decrease in the pullout force. The test results also show that the normal stress acting on the nail changes because of the volume-change tendency and arching effect of the soil being sheared around the nail. The post-peak decrease in the pullout force is mainly due to the reduction in the normal stress caused by the arching effect of soil around the nail. The conventional method of analysis tends to give a low interface friction angle and high interface adhesion. The correct interface parameters can be determined by taking the changes in the normal stress acting on the nail into account.Key words: arching effect, interface friction angle, laboratory test, loose fill, pullout resistance, soil–nail interaction.

Cellulosic building insulation versus mineral wool, fiberglass or perlite: installer's exposure by inhalation of fibers, dust, endotoxin and fire-retardant additives.

A task-specific exposure matrix was designed for workers installing building insulation materials. A priori, a matrix element was defined by type of task (installer or helper), type of work area (attic spaces or wall cavities) and type of insulation material (slabs from mineral wool, fiberglass or flax; loose-fill cellulosic material or perlite). In the laboratory a mock-up (full scale) of a one-family house was used for simulated installation of insulation materials (four replicates per matrix element). Personal exposure to dust and fibers was measured. The dust was analyzed for content of endotoxin and some trace elements (boron and aluminum) from fire-retardant or mold-resistant additives. Fibers were characterized as WHO fibers or non-WHO fibers. In support of the exposure matrix, the dustiness of all the materials was measured in a rotating drum tester. For installers in attic spaces, risk of exposure was low for inhalation of dust and WHO fibers from slab materials of mineral wool or fiberglass. Slab materials from flax may cause high risk of exposure to endotoxin. The risk of exposure by inhalation of dust from loose-fill materials was high for installers in attic spaces and for some of the materials risk of exposure was high for boron and aluminum. Exposure by inhalation of cellulosic WHO fibers was high but little is known about the health effects and a risk assessment is not possible. For the insulation of walls, the risk of installers' exposure by inhalation of dust and fibers was low for the slab materials, while a high risk was observed for loose-fill materials. The exposure to WHO fibers was positively correlated to the dust exposure. A dust level of 6.1 mg/m3 was shown to be useful as a proxy for screening exposure to WHO fibers in excess of 10(6) fibers/m3. In the rotating drum, slabs of insulation material from mineral wool or fiberglass were tested as not dusty. Cellulosic loose-fill materials were tested as very dusty, and perlite proved to be extremely dusty.