Dry Weight Of Sand Research Articles

Compressed stabilised earth block synergistically valorising municipal solid waste incinerator bottom ash and sisal fiber: Strength, durability and life cycle analysis

Compressed stabilized earth blocks (CSEB) represent an eco-friendly substitute for traditional building materials, predominantly utilizing earth. Municipal Solid Waste Incineration Bottom Ash (MSWIBA) is a by-product of municipal waste treatment that can be creatively repurposed in construction projects. This research explores integrating MSWIBA as a substitute for Earth in CSEB production to conserve natural resources and repurpose waste, potentially reducing its landfill disposal. The sisal fibers (SF), often regarded as by-products of agricultural processes, offer an intriguing research material. The SF was treated with a 5 % NaOH alkaline solution to improve the CSEB bonding, increasing the flexural strength. The study aims to determine the optimal mix of stabilizers, in addition to a 10 % cement content, using various percentages of MSWIBA (10–40 % by weight of dry sand) and SF content (0.25–1 % by weight of dry soil). These blocks undergo comprehensive tests to determine their strength and durability. Wet and dry compression, flexural tests and indirect tensile tests were used to assess strength qualities, while wetting-drying cycles and acid exposure were used to determine durability. MSWIBA replaces 20 % sand in CSEB satisfying the strength. However, exceeding this amount increases void content and lowers strength, emphasizing the importance of balanced proportions for best performance. The 20 % MSWIBA and 0.75 % SF combination enhanced the compressive strength by 6.45 MPa, flexural strength by 0.92 MPa and water absorption by less than 18 %. The durability test displayed increases in compressive strength of 14.7 % and flexural strength of 93.48 % and optimized water absorption rate. Furthermore, microstructural analysis has been performed on CSEBs and the results highlight the importance of balanced cement and SF proportions for structural integrity. Life Cycle Analysis (LCA) investigation shows that construction costs using CSEB are 12.24 % higher than those with FCBs. Additionally, the study suggests that CSEB with MSWIBA and SF will be an environmentally sustainable construction material, considering factors such as energy usage, Global Warming Potential, and other environmental considerations

Utilization of Different Additives in Improving Sandy Soil against Liquefaction

One of the main risks in low-densified sandy soils with the presence of water and an external force such as an earthquake is the generation of liquefaction. The influence of several types of reinforcement on liquefaction resistance, such as polypropylene fibers, geofibers, cement and polypropylene fibers with cement is shown in this study. Cyclic stress-controlled triaxial tests and cyclic strain-controlled triaxial tests were performed on saturated samples with and without reinforcements under undrained conditions. Cemented specimens were prepared with cement contents ranging from 0% to 3% by weight of dry sand and then cured for 3 days. The lengths of polypropylene fibers are 10 mm and 20 mm, respectively. The fibers were mixed with dry sand– cement mixes containing 0.50% and 1.00% by weight, respectively. Geofiber specimens were prepared in various arrangements. It was found that the liquefaction improvement factor (LIF) increased when fiber content and fiber length increased. The addition of geofibers increased the liquefaction resistance, as the number of layers increased. The addition of 3%C+1%F provided the best liquefaction resistance in this study compared with other additives. Finally, the reinforcement with cement and fibers is crucial for liquefaction resistanceof bitumen mastic should be considered beside the asphalt mixture performance and the bitumen rheological behavior. KEYWORDS: Liquefaction, Shear modulus, Cyclic stress, Geofiber, Polypropylene fiber.

Evaluation of Sand–tire Crumb Mixtures as Lightweight Fill Materials

ABSTRACT The reuse of scrap rubber crumbs mixed with sand as lightweight fills is considered as a sustainable application. However, the performance of sand–crumb mixtures and the optimum content of crumbs have not been consistent. The purpose of this study was to investigate the feasibility of using sand–crumb mixtures for applications such as embankment fills, backfilling for subgrades, and retaining walls, and assess the optimum crumb contents in the mix. Mixtures of fill sand and rubber crumbs with sizes of 1–2 mm at crumb contents of 0%, 10%, 20%, and 30% by weight of dry sand were tested in a laboratory for compaction and penetration using the California bearing ratio (CBR) test and for shear strength using direct shear tests. The dry unit weight, CBR, dilation, and friction angle decreased as the crumb content increased, while apparent cohesion was introduced in the mixtures with the addition of crumbs, and it increased with the crumb content. Sand–crumb mixtures were effective as lightweight fill materials over soft soils, but were not suitable as subgrade materials. Furthermore, sand–crumb mixtures with an optimum crumb content of 20% provided the maximum reduction in lateral earth pressure when they were used as backfill materials behind retaining walls.

Effects of multiscale carbon-based conductive fillers on the performances of a self-sensing cementitious geocomposite

In this study, the effects of multiscale conductive carbon fillers, including carbon nanotubes (CNTs), graphene nanoplatelets (GNPs), and carbon fibres (CFs), on the mechanical and microstructural properties, durability, and piezoresistivity of cementitious stabilised sand (CSS) were investigated. In this route, the surface of the CFs was modified via an oxidation process to improve their interfacial performance and dispersion. An optimum amount of hybrid CNT/GNP with different concentrations of CFs was incorporated into the CSS, and specimens were fabricated using the standard compaction method at the optimum water content . The interfacial properties of the CFs were studied by performing pullout tests and several chemical analyses. The variations in the mechanical and microstructural, durability, and piezoresistivity of the CSS, were investigated by various tests. In addition, the status of the specimens in terms of residual strain and damages was identified by the digital image correlation technique . The results showed a considerable improvement in the interfacial properties of the modified CFs in terms of physical and chemical bonding with the cement matrix . In addition, a combination of 0.17% CNT/GNP (1:1, by weight of dry sand) with 0.75% CF can improve the maximum dry density and mechanical properties, as well as the ductility and durability of the CSS. In addition, using multiscale conductive fillers resulted in a considerable enhancement in the electrical conductivity and piezoresistivity of the CSS. The outcomes indicate the immense potential of CNT/GNP/CF for the development of a sustainable self-sensing cementitious geocomposite . • A smart fiber-reinforced stabilised sand was developed for the first time for continuous monitoring of infrastructures. • The efficiency of CF was compared with CNT and GNP in terms of piezoresistivity behaviour enhancement of the cemented sand. • The fiber surface after treatment and their bonding with cement hydration products have been investigated by various tests. • Incorporation of the CF into the cemented sand containing CNT/GNP increased the elastic behaviour of the composite. • The CF- reinforced stabilised sand containing CNT/GNP demonstrated a proper piezoresistive behaviour.

Effect of using cemented sand as a replacement layer beneath a strip footing

ABSTRACT Soil replacement is an effective technique used in construction practices. Hence, several studies have considered the mechanisms to remove and replace mitigation in the past. This research represents an analysis of the efficiency of cemented stabilized soil replacement for improving the behaviour of weak soil. On the other hand, the optimum design for foundation depends on the soil properties beneath these foundations. One of the best solutions for this challenge is to increase the shear parameters and reduce the compressibility for the foundation soil using cemented sand mixture technique. An experimental program was conducted to study the impact of cement stabilization on the geotechnical characteristics of sandy soils, furthermore, five cement ratios (3%, 5%, 7%, 10% and 15% by dry weight of sand) have been mixed with sandy soil and tested under compaction and shearing. The results illustrated that the maximum dry unit weight of sand increases with the increase in cement content whereas the optimum moisture content decreases marginally with the increase in the cement content. In addition, increasing cement content leads to an increase of cohesion, friction angle and Young’s modulus. This paper is considered a serious attempt to estimate the optimum cement ratio required to improve the mechanical properties of soil replacement under a strip footing. Numerical modelling for this footing was done by Plaxis software. The results illustrated that adding the cement mixture improves the behaviour of footing. The effect of the replacement extension on the strip footing is also analyzed, where; the results indicated that the optimum replacement extension is equal to the thickness of replacement. This study is based on the limitation of the herein proposed numerical model and its properties.

Effect of silica fume on the ultrasonic pulse velocity of cemented sand

One of the geotechnical engineering strategies for dealing with weak soils in a construction site is to modify their mechanical properties with the aid of soil improvement techniques. Chemical stabilization of soil using cement is one of these effective approaches that can considerably enhance workability and shear strength parameters of soil. However, very limited investigations have been carried out to reveal the effect of silica fume on the ultrasonic pulse velocity (UPV) and the ultrasonic stiffness (Eu) of cement-treated sandy soil. For this purpose, in the present research, a series of UPV tests were performed on sand-cement-silica fume specimens. The cement percentages were 3, 5 and 7% and silica fume contents were 0, 0.25, 0.5 and 1% by weight of dry sand. The cylindrical samples were prepared and cured for 3, 7, 14, 28, 42 and 56 days and tested. The results show that inclusion of silica fume to the cemented sand increases UPV and Eu which this enhancement is more pronounced at longer ages.

EFFECT OF CEMENT ON COMPRESSIBILITY AND SWELL OF SAND-EXPANSIVE CLAY MIXTURES

This paper investigates the effect of adding low percentages of cement on the swelling and compressibility characteristics of sand-expansive clay mixtures. The use of highly plastic clay is known for reducing the hydraulic conductivity which is the main goal of waste containment barriers. However, liners can act as cover layers, road base, or a supporting ground. Excessive swell is likely to cause damage to light structures. Recent studies called for using clay with low plasticity that is just enough to fill the voids. Other researchers suggested adding fillers of fine powder. This study is an attempt to reduce the high plasticity with the addition of cement. The expansive clay used in this research was obtained from Al-Qatif region in the Eastern Province of Saudi Arabia. For these mixtures, the sand was considered the host material, and the clay content varied between 10% to 40% by dry weight of sand. The proposed cement content is put as low as 1, 2, and 4% by the dry weight of mixture at curing periods of 1, 7, and 28 days. A series of onedimensional odometer tests were conducted to evaluate the swelling potential, swelling pressure, and compressibility characteristics of mixtures. Laboratory compaction tests were performed to determineoptimum moisture content and maximum dry density. The addition of cement was found to improve the engineering properties of the mixtures and stabilize and control the swell and compressibility of the liner material.

Engineering properties of plastic waste reinforced sand

A series of triaxial compression tests were performed to evaluate the benefits of plastic wastes and investigate the engineering properties of sand reinforced with these materials. In this research, the effects of plastic waste contents (0, 0.25, 0.5, 0.75, and 1% by dry weight of sand), types of plastic wastes -polyethylene terephthalate (PET) and polypropylene (PP) fibers- and confining pressures (50, 100 and 200 kPa) on the behavior of Babolsar sand were investigated. The values of deformation modulus (up to 84%), peak (up to 7 times of the unreinforced sand) and steady state shear strength increased with reinforcement. Also, axial strain at failure for fiber-reinforced sand increased up to 1.5 times of unreinforced one (from 3.36% to 8.53% for 1% PP usage at 50 kPa confining pressure). Therefore, it can be generally stated that the use of plastic wastes in the sand leads to low cost soil reinforcement and also lessens the disposal problem of these kinds of wastes.

CBR behavior of sandy soil reinforced by geofiber material

Abu Dhabi sand lacks the required engineering properties to suffice as pavement base course, subbase course, subgrade and as a foundation-support layer under buildings and various structures. Low bearing capacity is manifested on the roadways as differential settlement, waviness and undulations. Stabilization of this type of sand is one of the major geotechnical challenges in practice. In this study the sandy soil was improved by mixing with geofiber. Three different levels of geofiber was added to the sandy soil; 0.1, 0.2 and 0.4% by dry weight of sand. The results showed great increase in shear strength as indicated by the CBR values. The CBR values have increased from 19 to 55 for 0 and 0.4% geofiber content respectively.

Influence of Silica Fume on the Geotechnical Characteristics of Cemented Sand

It is well recognized that the addition of cement to sand is one of the environmental and economic techniques in soil stabilization. However, with respect to silica fume, its impact on the characteristics of cemented sand has not been comprehensively investigated. For this purpose, a series of standard Proctor compaction, unconfined compression, pH and microstructure tests including field emission scanning electron microscope, X-ray diffraction and atomic force microscopy tests were carried out in this research to explore the influence of silica fume on the geotechnical characteristics of cemented sand. Cement in percentages of 3, 5 and 7% and silica fume in percentages of 0, 0.25, 0.5 and 1% by dry weight of sand were utilized. For unconfined compression and pH tests, samples were cured for different curing times of 3, 7, 14, 28, 42 and 56 days. The results indicated that silica fume particles increase maximum dry unit weight of sand–cement mixtures and reduce their optimum moisture content. Moreover, silica fume improves unconfined compressive strength of cemented sand which the impact of this improvement is more obvious for samples with longer curing time. According to the results obtained by unconfined compression and pH tests, it was detected that there are optimum values of curing time and silica fume amount at which strength of silica fume–cemented sand enhances significantly. Furthermore, some relations were proposed between stiffness and unconfined compressive strength of silica fume–cemented sand. Finally, the results of microstructure analysis confirmed the results found through unconfined compression tests.

Dynamic Response of Model Footing on Hair Fiber-Reinforced Sand

Free vibration tests were conducted on scaled model footing resting on unreinforced and hair fiber-reinforced sand to determine the dynamic characteristics of the soil-foundation system. The sand was reinforced with the random mixing of unsorted human hair fibers collected from barber shops and compacted to a relative density (RD) of 80% in the model test tank. The percentage of fiber inclusion was varied up to 1.0% by dry weight of sand. The reinforced sand was prepared with an initial moisture content of about 2–3% to obtain the consistent uniform mixing. The sand bed was filled in eight layers of 10 cm each in loose condition. Each layer was compacted using a calibrated plate vibrator to achieve the desired relative density before filling the next layer. The free vibration tests were conducted in model test tank by varying the depth of fiber reinforcement (dr) and the width of the fiber reinforcement (wr) for different percentage of fiber inclusions, viz., 0.5%, 0.75%, and 1.0%. The results demonstrated that addition of even 0.5% human hair fiber with the sand can help in shifting the natural frequency of the soil-foundation system.

Influence of Polyurethane Polymer on the Strength and Mechanical Behavior of Sand-root Composite

Vegetation has good application in slope stabilization, but its beneficial effects on reinforcing topsoil are generally limited by the soil properties it was cultivated in. This study aims at evaluating the strength improvements of sand-root composite by treating with polyurethane polymer and hence investigating the mechanism of polymer-root-soil interactions. Vegetation roots were selected and mixed with dry sand and polymer solution to prepare remolded specimens. A series of experimental tests were then performed at different percentages of root content (0, 0.4, 0.8, 1.2, and 1.6 % by weight of dry sand) and polymer content (1, 2, and 4% by weight of dry sand) to evaluate the shear parameters and unconfined compressive strength (UCS). The combined mechanism was studied by scanning electron microscopy (SEM) images. The results showed that the strengthening effect has greater efficiency with higher polymer content. Through varying contents of vegetation root, it was found that low root content induced an undesirable weakening effect on the strength of the treated soil. However, this situation was somewhat improved with the increase in root content. The good flexibility of polymers not only promote the capacity of soil to energy absorption, but also impart good ductility to soil. The presence of polymers greatly strengthens soil stability due to its special network structure, by which the improved shear resistance at the root-soil interface provides sufficient anchorage effect for the tensile strength of roots to be fully mobilized. Overall, the synergistic effect of root reinforcement and polymer treatment has the potential for its use in soil stabilization.

Liquefaction Characteristics of Sand With Polypropylene Fiber at Low Confining Stress

The present study evaluates the liquefaction characteristics of Ottawa sand with polypropylene fiber using cyclic triaxial test. A series of stress-controlled cyclic triaxial tests were performed at 34.47 kPa (5 psi) effective confining pressure. Specimens of clean Ottawa sand, and sand containing 0.05, 0.075, 0.1, and 0.3% polypropylene fiber by dry weight of sand were tested at 0.2, 0.25, 0.3, and 0.4 Cyclic Stress Ratio (CSR). Results show that a significant improvement in liquefaction resistance when the polypropylene fiber content exceeded beyond 0.075% at 34.47 kPa effective confining stress.

The influence of micro silica on the compaction properties of cemented sand

In this experimental research, a series of standard Proctor compaction tests have been performed to explore the effect of micro silica on the compaction properties of cemented sand. The cement contents were 3, 5 and 7% and micro silica contents were 0, 0.25, 0.5 and 1% by weight of dry sand. The results showed that micro silica particles increase maximum dry unit weight of sand-cement mixtures and decrease their optimum moisture content. The results of Scanning Electron Microscope (SEM) images confirmed the results of compaction tests and indicated that micro silica can effectively fill the pores of sand-cement mixtures which can lead to creation of a cement-treated sand mixture with compact microstructure.

Effects of silica fume on cemented sand using ultrasonic pulse velocity

When the geotechnical engineering projects have to be built on weak soils, problems related to bearing capacity and settlement arise. Chemical stabilization of soil using cement is a popular and effective technique that can significantly improve workability and shear strength of soil. However, very limited studies have been conducted to reveal the effect of silica fume on the engineering properties of cement-stabilized sandy soil. For this purpose, in the present study, a series of laboratory tests including standard Proctor compaction, unconfined compression and ultrasonic pulse velocity tests were carried out on sand-cement-silica fume samples. Moreover, it has been attempted to investigate the relation between ultrasonic pulse velocity and unconfined compressive strength of cemented sand containing silica fume. The cement contents were 3, 5 and 7% and silica fume contents were 0, 0.25, 0.5 and 1% by weight of dry sand. The cylindrical specimens were prepared and cured for 3, 7, 14, 28, 42 and 56 days and tested. The results show that inclusion of silica fume to cemented sand increases maximum dry unit weight, unconfined compressive strength and ultrasonic pulse velocity while decreases optimum moisture content. In addition, according to the obtained results, acceptable correlations exist between ultrasonic pulse velocity, unconfined compressive strength and stiffness.

Measurement of Unit Weight of Dry Sand Using Piezoelectric Sensor

Recently, an electro-mechanical impedance (EMI) technique has found wide application in the monitoring of concrete structures. This EMI technique was employed for measuring the unit weights of various grain sizes of sand and the relevant process is reported herein. A piezoelectric sensor (PZT, i.e., lead zirconate titanate sensor) was imbedded into small, medium, and large-sized grains of the Nakdong river sand and a surcharge was applied. The effect of an increase in unit weight owing to the surcharge was investigated in terms of the resonant frequency (peak frequency) and corresponding conductance at resonant frequency (peak conductance). A ceramic-coated PZT sensor was used to prevent the occurrence of a short circuit. The measured peak frequency and conductance from the PZT sensor were correlated with the unit weight of sand. With an increase in the unit weight of sand, the peak PZT frequency was found to have increased, however, the peak conductance was seen to have decreased. The peak PZT frequency and conductance were seen to be strongly correlated with the unit weight of Nakdong river sand except for the peak conductance of large grain sized sand.

Effect of Sisal Fiber and Polyurethane Admixture on the Strength and Mechanical Behavior of Sand.

One major problem related to sandy soil is its low shear strength and cohesion in engineering. Although much effort has been made to strengthen sand mass with satisfactory performances, most undertakings lack environmental considerations. Thus, a combination of natural fiber and macromolecule polymer material attempts to achieve both strength and eco-friendliness. In the present investigation, sisal fiber (SF) and water-based polyurethane (PU) were used to reinforce sand. A series of unconfined compression tests were carried out on sand specimens at different percentages of fiber contents (0.2%, 0.4%, 0.6%, and 0.8% by weight of dry sand) and polymer contents (1%, 2%, 3%, and 4% by weight of dry sand). The results showed within our test range that the unconfined compressive strength (UCS) as well as post-peak strength of specimens increase with fiber and polymer contents. The inclusion of fiber and polymer significantly improve the ductility of specimens. The effect of dry densities on UCS were studied with three proportions. It is found that a high dry density led to an increase of UCS due to an effective contact area increase. The interactions were studied by observation through scanning electron microscopy (SEM) images. The presence of water-based polyurethane has the potential to improve the interparticle cohesion of sand due to its unique network membrane structure. The fiber reinforcement benefit depends strongly on the friction, interlocking force, and bond strength at the interface.

Experimental investigation of flexure resistance performance of bio-beams reinforced with discrete randomly distributed fiber and bamboo

Microbial induced calcite precipitation (MICP) can bond sand particles together to improve the mechanical properties of sandy soil. This environmental-friendly technique has potential applications on construction materials such as bio-bricks and bio-beams. This study is to investigate the flexure resistance performance of bio-beams by adding discrete randomly distributed fiber and bamboo materials with multiple immersing MICP treatment. Different fiber proportions (0.1%, 0.2%, 0.3% and 0.4% by weight of dry sand) were used. MICP treated bio-beams were also reinforced by five different arrangements of bamboo strips. Four-point bending tests were conducted to evaluate the flexure behavior of fiber reinforced and bamboo reinforced bio-beams. Results showed that adding fiber in the MICP treated bio-beams can increased the ductility. The optimum fiber content was around 0.3%. Addition of 0.3% fiber can significantly prevent the post peak flexure strength loss and improved the ductility of bio-beams which had 400 kPa residual strength at 15% failure strain. Bamboo reinforced bio-beam can improve the flexure strength from 890 kPa to 1750 kPa. Meanwhile, multiple immersing MICP treatment can significantly improve the flexure strength of bio-beams up to 3.0 MPa, but the ductility of fiber reinforced bio-beam reduced after multiple treatment.

Development of bio-cemented constructional materials through microbial induced calcite precipitation

Microbial induced calcite precipitation (MICP) is an environmentally friendly technology to bond sand particle together to form sandstone like materials. In this paper, MICP-treated bio-specimen was developed through MICP. The property of bio-specimen was compared with beams or bricks made through lime modification and cement modification. Ottawa sand was used in MICP-treated bio-specimen preparation. The proportion of lime or cement was in the range of 10–40% by weight of dry sand. The four-point bending tests, brick compression tests and unconfined compression tests were conducted. The test results indicated that flexure strength of MICP-treated bio-specimen was 950 kPa which was similar to flexure strength of 20–25% cement-treated sand beams, but was much higher than flexure strength of 30% lime-treated sand beams. The brick compression strength of MICP-treated bio-specimen achieved 500 kPa, which was similar to brick compression strength of 30% lime-treated sand bricks. The unconfined compression test results showed that the unconfined compression strength (UCS) of MICP-treated bio-specimen (1300 kPa) was higher than UCS of 10% cement-treated specimen (900 kPa), and much higher than UCS of lime-treated sample (around 140 kPa). The relative uniformity of precipitated CaCO3 distribution was achieved through the sample immersing preparation method. SEM images showed that failure pattern of MICP-treated, cement-treated and lime-treated specimens were bond-particle failure.

Shear strength behavior in the interface of contaminated soil with bio-diesel oil and geosynthetics

Abstract This article aims to present the shear strength of soil-geosynthetic interface through laboratory tests. Shear strength of a soil-geosynthetic interface is defined as the primary parameter of slope stability in cases where the potential slip surface runs along a geosynthetic. Besides, palm biodiesel contamination can affect the geotechnical properties of foundation soils. In this study, interface interaction between soil and various geosynthetics, namely A, B, and C was investigated in term of shear strength parameters. The type of palm oil used for contaminating is B20 palm biodiesel ranging from 3% to 10% by the weight of dry sand. The objective of this research is to assess the shear strength parameters at the soil-geosynthetic interface. For this purpose, test specimens of both clean and contaminated sample with different geosynthetics were tested under direct shear test in order to evaluate their shear strength. Results were analyzed based on the behavior of three different geosynthetics as reinforcements and contaminated mining sand. The results of direct shear tests indicate that shear strength varies considerably along the soil-geosynthetic interface. It was found that the shear strength of reinforced sand with geosynthetic C was increased by almost 1.3 times as compared to that of the unreinforced test specimen. A notable discovery is that the reinforced sand with geosynthetic C could improve the shear strength of the soil sample to protect the slopes, particularly shallow foundations on mining sand. However, further laboratory and field investigations are recommended.