Clay Research Articles

Prediction Of Compression Index For Lateritic Soil Using Transformed Variable

The information on the compression index of a soil is vital in geotechnical design, but its determination is expensive and time consuming. Most models relating compression index and basic soil properties are usually based on soil types. This work seeks to develop a model relationship between compression index and basic soil properties for lateritic soils. Selective transformation method which involves testing some general functional forms, to choose the model that best characterizes the data relationship was adopted. Secondary soil data were obtained from existing literature on soil properties of lateritic soils. Liquid limit was adopted as the independent variable in the modeling exercise as it is easily obtained in comparison to clay content and final void ratio. The square root transformation model has both constant and coefficient terms significant at 5% level of confidence. The model performed better than other empirical models using statistical criteria. It is believed that the model will assist greatly in construction activities in areas where consolidation test equipment and trained manpower are unavailable.

REVIEW OF NANO MATERIALS FOR PREDICTING STRENGTH AND VOLUME CHANGE BEHAVIOUR OF EXPANSIVE SOILS

Expansive soils are problematic to Civil Engineering by increase and decrease its volume due to movement of water in and out. This kind of soils is portrayed by its outrageous hardness while drying and with high swelling process on the wetting. Several researches during the past 20 years have proposed different nano materials for the soil stabilization approaches to counter the hazards present in the soils. This paper elaborates various studies on different nano materials are nano silica, nano clay, nano composites were used to control the behavior of expansive soils on the current soil stabilization. In this paper, a state-of-art of the nano materials soil stabilization succinctly summarized. The nano materials are critically reviewed in terms of their soil stabilization with their strength and limitations. The review highlights the need for prediction of materials that are conceptually simple yet efficient for use in conventional engineering practices for different types of expansive soils for sustainable development purpose.

Performance analysis and test of a maize inter-row self-propelled thermal fogger chassis

In view of the difficulties in weeding and plant protection in the middle and late period of maize planting, this paper proposed a self-propelled thermal fogger chassis. According to the theoretical calculation and agronomic requirements for maize planting, the structure and working principles of the self-propelled thermal fogger chassis were introduced. On this basis, the multi-body dynamics model of chassis structure was established, and the chassis traction, steering and obstacle surmounting performances were also analyzed. Then the rationality and the feasibility of the design were verified through the furrow running test and test equipped with thermal fogger. Test results showed that, the traction performance improves with the decrease of soil deformation index and increase of cohesion, and when track pre-tensioning force was about 1000 N, the machine had a good traction performance; with the decrease of the soil deformation index and the increase of cohesive force, the stability of the single side brake turn of the chassis becomes better; on the contrary, with the increase of the tightness of the crawler, the steering radius turns smaller and the steering stability becomes worse. Under heavy clay, with the pre-tensioning of 1000 N, the machine has better steering stability and smaller turning radius. The obstacle-surmounting simulation result shows that on sandy soil road, the maximum climbing angle for the chassis is 42°, the height of vertical obstacle crossing is 170 mm and the trench width is 440 mm. The study provides a reference for the design of plant protection machinery in the middle and late stages of maize planting. Keywords: maize inter-rows, intelligent chassis, traction performance, steering performance, obstacle surmounting performance DOI: 10.25165/j.ijabe.20181105.3607 Citation: Chen L Q, Wang P P, Zhang P, Zheng Q, He J, Wang Q J. Performance analysis and test of a maize inter-row self-propelled thermal fogger chassis. Int J Agric & Biol Eng, 2018; 11(5): 100–107.

Effects of irrigation water regime, soil clay content and their combination on growth, yield, and water use efficiency of rice grown in South China

To investigate the effect of irrigation regime, soil clay content and their combination on growth, yield, and water productivity of rice, a shelter experiment was conduct using Randomized Complete Block Design (RCBD) with a factorial arrangement of treatments with four replications. Irrigation regime was the main treatment investigated, set in three levels as R(30 mm-100%) (100% of saturation and 30 mm flooded), R(30 mm-90%) (90% of saturation and 30 mm flooded) and R(30 mm-70%) (70% saturation and 30 mm flooded), respectively. The sub-treatment was soil type, set in three levels as 40%, 50% and 60% clay content, respectively. Results showed that irrigation regime and soil clay content had significant effects on growth, yield and water productivity of rice. However, their combination showed no significant impact on panicles number, root biomass, harvest index and irrigation water productivity. Higher soil clay content results in increase in growth, yield, and water productivity of rice. The total water consumption during R(30 mm-100%) was higher than that during R(30 mm-90%) and R(30 mm-70%) because the latter two saturation levels led to the cracking of soil and decrease of total number of irrigations. Cracks were consistently getting more serious with the reduction in soil water content and the increase in soil clay content. Cracks in soil will preferentially become the major routes of water losses, thus water percolation during R(30 mm-70%) was higher than that during R(30 mm-90%) and R(30 mm-100%) after each irrigation event. The total water use under R(30 mm-70%) exceeded the water consumption under R(30 mm-90%) due to the great amount of soil cracking as well as the excessive volume of standing water depth. Considering water consumption and grain yield, the following conclusion can be reached: (i) The reduction in water consumption was greater than the reduction in grain yield in the case of drying soil 10% below saturation before reflooding. (ii) The reduction in water consumption was less than the reduction in grain yield in the case of drying soil 30% below saturation before reflooding; (iii) The increase in water use was greater than the increase in grain yield in the case of maintaining soil moisture at 100% of saturation before reflooding. Therefore, the water use efficiency was recorded in the order of R(30 mm-90%) >R(30 mm-100%) >R(30 mm-70%). Keywords: irrigation regime, clay content, combination, growth, yield, water productivity, rice DOI: 10.25165/j.ijabe.20181104.3895 Citation: Hamoud Y A, Guo X P, Wang Z C, Chen S, Rasool G. Effects of irrigation water regime, soil clay content and their combination on growth, yield, and water use efficiency of rice grown in South China. Int J Agric & Biol Eng, 2018; 11(4): 144-155.

Ash Deposits CHP – as an Additional Source of Raw Material for Construction Production

Issues related to the rational processing of industrial waste and the protection of the environment are of particular importance. The prerequisite for writing this article was the ecological situation in Kazakhstan. Currently, many industrial enterprises have accumulated and continue to accumulate man-caused waste of production processes that not only pollute the atmosphere and, washed away by rain and snow, pollute the water basin of nearby areas. The work of CHP is one of the main polluters of the environment, mainly the air basin. CHP plants operating on traditional types of fuel contribute up to 30 % of the volume of harmful emissions of the atmosphere, pollute the land and water with combustion products and sewage. Technogenic wastes occupy hundreds of thousands of hectares of fertile land. In them, the content of non-ferrous metals reaches up to 5 %, iron up to 45 %, in addition, some of them contain noble metals. The bulk of this waste is siliceous materials, which are the main source of building materials. In Kazakhstan, as yet, they have not been engaged in the utilization of ash, these are technogenic waste from the thermal power station. Known methods of processing such raw materials do not fully comply with modern requirements of scientific and technological progress. Dumps of ash and slag materials occupy large areas, and their content requires significant operating costs, which affect the increase in the cost of production of energy. They are a source of environmental pollution, present a danger to public health and a threat to the plant and animal life of the surrounding areas. Especially dangerous are ash dumps located near water basins (rivers and lakes), because of the possible breakthrough of dams. Effective utilization of coal energy coal plants can help significantly reduce the negative impact on the environment and improve the economic performance of the enterprise. In general, ash is widely used in various industries and has good market prospects. There are available technologies for ash utilization, some of which are widely used commercially. At present, the main quantity of ash is used in the construction industry - this is the production of cement, bricks, cellular concrete products, slag blocks, lightweight aggregates, roofing material, expanded clay, construction of dams for ash dumps, construction and repair of roads. The use of ashes and slags of CHP as building materials is the most ambitious direction and can solve the problem of building materials shortage in the regions of Kazakhstan in the future. Due to the use of ash waste, we can save up to 30 % of cement and more than 50 % of natural aggregates, thereby reducing the thermal conductivity of concrete will reduce the mass of buildings and structures. To attract investments in order to increase the level of processing and use of ash waste, it is possible to use interest in the purchase of ash and slag from the thermal power stations of Kazakhstan in those Western European countries and the Middle East, where there are not enough sources of mineral raw materials in sufficient quantities. The solution of the above problems is necessary to increase the level of utilization of ash waste with a view to reducing their accumulation, improving the environmental situation in the vicinity of the CHP plant, as well as receiving income from the sale of products produced on the basis of ash waste.

A COMPOSITE SORBENT BASED ON BENTONITE-LIKE CLAY AND HYDROXYAPATITE

The results of development of a composite sorbent based on bentonite-like clay and synthetic hydroxyapatite and investigation of its properties are discussed. Morphological, structural characteristics and phase composition of the experimental sorbents are studied by X-ray diffraction analysis, scanning electron microscopy, and infrared spectroscopy. The composite sorbent has been found to have more sorption capacity toward Pb 2+ ions (1250.3 mg/g) as compared to the initial sorption active materials and conventional sorbents (activated carbon, bentonite, zeolites, etc.) as well as some composite sorbents based on hydroxyapatite. The developed composite sorbent provides 100% purification of water from Pb 2+ ions at their initial concentration in an aqueous solution equal to 200 mg/g and sorbate : sorbent mass relation equal to 1:10.

<b>A Look at Gender Relations in the Production of Clay Things</b>

In this article, we discuss the gender relations in the production of pottery – the “clay things”. Firstly, we draw a dialogue with gender studies in Archeology. Next, we explain the use of the category "ceramics of local / regional production". We present in detail the operative chain for the production of ceramic artifacts in the district of Santa Rita, city of Ouricuri, Pernambuco. Finally, we draw some comparative reflections between the information derived from Santa Rita and other studies focused on ceramic production in traditional communities of the semi-arid region, in northeast of Brazil, evidencing that the gender action does not have a fixed set of norms, being marked by processes that affect and are affected by other social spheres.
 
 
 Um Olhar para as Relações de Gênero na Produção das Coisas de Barro
 
 Neste artigo, discutimos as relações de gênero na produção das coisas de barro. Primeiramente, traçamos um diálogo com os estudos de gênero na Arqueologia. Em seguida, explicitamos o uso da categoria “cerâmica de produção local/ regional”. Passamos então, ao detalhamento da cadeia operatória de produção de artefatos cerâmicos no distrito de Santa Rita, município de Custódia, Pernambuco. Por fim, traçamos algumas reflexões comparativas entre os dados advindos desse estudo e outras pesquisas voltadas à produção cerâmica em comunidades tradicionais do semiárido nordestino, evidenciando que a ação de gênero não está presa a um conjunto fixo de normas, sendo marcada por processos que afetam e são afetados por outras esferas sociais.

<b>The Potters and the Archaeologist: the Clay in the Construction of Different Bodies</b>

In this article, guided by experienced ceramists, I was able to delve into the pottery productive universe, not only observing these ceramist women, but thinking with my hands. This commitment to learning a motor skill has allowed new questions to surface, modifying my point of view regarding the artifact. As in the productive process that I have been learning, this text has come and go, and these retakes have been part of its modeling process, of my own learning process. And so, it may seem overly intersubjective, because it approaches frontier paradigms. Focusing on the gestures, the production of the text also gave the groping, with the body being the guide on the way. The gesture is pure ubiquity, being at the same time intellectual and material denotes the know-how itself; or rather, more than that, it allows the doing-being because in building the materiality develops at the same time, the identity. As Leroi-Gourhan (1965, p. 44) said long time before, "it is in what produces or does, not in what is, what a human hand manifest itself as such".
 
 As Ceramistas e a Arqueóloga: a Argila na Construção de Corpos Distintos
 
 A olaria é uma técnica corporal exigente que requer um corpo ativo. É preciso (constantemente) atenção voluntária, treino, repetição, abertura à crítica e autocrítica, tolerância à dor (e de novo). Mas é fundamental saber montar e desmontar - sempre como processo contínuo – o sujeito e a matéria, a pessoa e o objeto, de forma inseparável. O barro é também uma pessoa e a pessoa um corpo-máquina, ciborgue (Haraway, 2000). Um corpo molda o outro de forma relacional (Joyce, 2000) em um processo recíproco de objetivação-subjetivação (Santos-Granero, 2009). 
 Para as ceramistas com as quais convivo nos espaços urbanos, só existe o ser no fazer, esses verbos se constroem mutuamente e se enredam, não há vida sem argila. Ser essa pessoa tem estreita relação com o fazer cerâmico. Como já aprendemos faz tempo com Simone de Beauvoir e Judith Butler, nos tornamos mulheres nessa construção material e simbólica; e distintas umas das outras, mulheres situadas. Nesse sentido, interessa aqui debater algumas dessas construções e sociabilidades em fazer-ser uma mulher ceramista em um contexto urbano. Elas se constroem em um esforço voluntário, consciente e proativo em seu ofício, como mulheres-ceramistas. Entre ceramistas a máxima “sinto, logo sou” é potencializada, e é então um corpo ativo que aplica uma teoria viva ao seu meio ambiente (Le Breton, 2016). 
 Nesse artigo pretendo interligar pessoas, coisas e fatos, para construir uma narrativa (parcial) sobre a tecnologia cerâmica e os diferentes corpos que ela produz. A perspectiva, no entanto, não é minha nem delas sendo ao mesmo tempo também nossa. É a argila, narradora da história, que dita o tempo, constrói, conecta e transforma os diferentes corpos. É essa perspectiva da materialidade que desejo seguir, incluindo os gestos técnicos como perspectiva teórico-prática.

Amelioration of mechanical and rheological characteristics of a ceramic Slip by adding of bentonite

This work is a contribution to the amelioration of the mechanical and rheological properties of a slip of ceramic used in the ceramic fabrication process. A study of characterization of slip of ceramic modified by bentonite has been accomplished chemically, physically, mechanically and rheologically. Chemical analysis showed that the slip modified by bentonite consist essentially of silica with a ratio (SiO_2/Al_2 O_3) average equal to 3.5 and the ratio of clays (Al2O3/SiO2) is relatively stable with increasing percentage of bentonite in the slip, with an average 0.28. The mechanical and rheological tests showing that increasing the percentage of bentonite in base slip caused an increase in the mechanical resistance, the yield stress and rapid decrease in density of the slip.

Earthquake performance assessment of low and mid-rise buildings:Emphasis on URM buildings in Albania

This study focuses on the earthquake performance of two URM buildings having typical architectural configurations common for residential use constructed per pre-modern code in Albania. Both buildings are unreinforced clay brick masonry structures constructed in 1960 and 1984, respectively. The first building is a three-storey unreinforced one with masonry walls. The second one is confined masonry rising on five floors. Mechanical characteristics of masonry walls were determined based on experimental tests conducted according to ASTM C67-09 regulations. A global numerical model of the buildings was built, and masonry material was simulated as nonlinear. Pushover analyses are carried out to obtain capacity curves. Displacement demands were calculated according to Eurocode 8 and FEMA440 guidelines. Causes of building failures in recent earthquakes were examined using the results of this study. The results of the study showed that the URM building displays higher displacement and shear force demands that can be directly related to damage or collapse. On the other hand, the confined one exhibits relatively higher seismic resistance by indicating moderate damage. Moreover, effects of demand estimation approaches on performance assessment of URM buildings were compared. Deficiencies and possible solutions to improve the capacity of such buildings were discussed.

Comparative analysis of physical and chemical characteristics of selected clays deposits found in Kebbi State, Nigeria

The intent of this paper was to explore the physical and chemical characteristics of clays in Kebbi State, Nigeria, and the clays were compared with standard clay which is considered with highest quality standard in casting. Clay’s deposits from Dukku River along River Rima, Jega River which is the tail end of River Niger and Yauri were investigated for their potentials as raw materials used for casting and ceramic industries. Samples were collected from three local governments’ areas at the bank of the Rivers. Chemical analyses of individual clay were determined by employing four different techniques as follows; Complexiometric Titration, Atomic Absorption Spectrophotometer (AAS), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF). The data collected from the analyses revealed that the structures of clay minerals were mainly kaolinite, Smectite (bentonite), and illite, and non-clay minerals for the three places were mainly quartz, feldspars and gibbsite. The results obtained revealed high silicate clays and moderate alumina content with trace elements of oxides (Fe2O3, CaO, K2O, TiO2, MgO, MnO, Na2O) also present within acceptable limits. Physical tests results at 900°C and 1300°C were used to determine firing shrinkage, colour, and modulus of rupture, bulk modulus, apparent density, crack formation, apparent porosity, water absorption, and bulk densities. The modulus of rupture, bulk densities, and fired linear shrinkage of all the samples increase with increasing firing temperature. The findings of this work revealed that the clays minerals from Dukku and Yauri had the necessary properties for the foundry work and refractory applications, but clays from Jega, can be exploited for commercial purposes after beneficiation by reducing the level of iron, quartz and other impurities. Key words: Clay minerals, chemical analysis, firing characteristics, oxides.

GENETIC PROGRAMMING FOR BRICK'S CHEMICAL ANALYSIS MODELLING

This study is part of the search for a sediment management methodology and the basic material that is designed for the manufacture of fired brick, in which we tackle the problem of choosing the mud samples from dredging the Algerian dams in particular (Bouhanifia dam western Algeria) and the choice of clay that comes from different deposits. We propose an approach for sampling using a computer optimization model that allows solving and optimizing a characterization to retain the best adapted sample (chemically) using the genetic algorithm.Keywords: Sludge- Dredging- Sample- Chemical Characterization- Brick-Optimization Methods- Genetic Algorithm.

Effect of Different Proportion of Find Sand and Silt on Swelling Pressure of Expansive Clays

Effect of Different Proportion of Find Sand and Silt on Swelling Pressure of Expansive Clays

Original sediment composition of the Lower Cretaceous lacustrine tight-oil mudstone and influences on diagenesis and organic matter content, the Erennaoer Sag in Erlian Basin, NE China

Abstract The original sediment composition is of great value to providing an understanding of depositional environment and hydrocarbon-generation potential, but it is easily altered by diagenesis and difficult to recognize. In this study, we examine carbonate-rich tight-oil mudstones of the Lower Cretaceous Arshan Formation in the Erennaoer sag of the Erlian Basin as an example. Based on analyses of mineralogy, stable carbon and oxygen isotopes, and trace/rare earth elements, the original composition of the Arshan mudstones has been reconstructed. Results show that the original Arshan mudstone composition was mainly siliciclastic detritus, tuffaceous and clay matrix, which has a major impact on diagenesis and organic matter content. The erupted volcanic ashes were beneficial to the introduction of nutrients, an increase in biomass and an associated increase in to the preservation of organic matter, which has been suggested by an improvement of TOC of Arshan tuffaceous mudstones, with average contents of 2.82%. The volcanic ashes in the studied mudstones had also enhanced methanogensis during the shallow burial. Additionally, the early alteration products of authigenic minerals include analcime or zeolite, most of which is entirely altered to analcime and chlorite. The formation of major eogenetic carbonate cements include early dolomite and calcite, which were related to volcanic materials and methanogenesis at shallow depths.

Le monastère de Qol-e-Tut à la lumière des fouilles archéologiques

Le monastère se déploie sur une pente, au sud de la citadelle de Kaboul, dans une zone riche en sites bouddhiques. Des fouilles entamées en 2013 avec l'Institut afghan d'archéologie ont permis de dégager notamment jusqu'ici dix terrasses occupées par dix huit chapelles, abritant les restes de bodhisattva colossaux en argile séchée et polychromée. Leur nombre suggère que le site leur était dédié. Seule une chapelle est occupée par un Bouddha, monumental, enseignant, sans équivalent dans la région par son geste, sa taille et son raffinement. Au cœur de l'ensemble, une salle de prière (?) à banquettes, dotée d'un élément central circulaire énigmatique, encadré de quatre bases de piliers, ouvrait sur trois chapelles. Les monnaies et céramiques découvertes à Qol-e-Tut indiquent que son existence s'est étendue du 6ème siècle au plus tôt, à la fin du 11ème siècle au moins. Ce site complexe témoigne donc du remarquable développement de l'art bouddhique à Kaboul, de son originalité et de sa pérennité, sous le règne des Hephtalites, puis des Hindu-Shahi, ainsi que le suggéraient déjà nos fouilles du monastère de Tepe Narenj, situé à proximité. Ceci contredit les récits anciens d'historiens arabes et persans, datant de la deuxième moitié du 7ème siècle l'islamisation de Kaboul.

Assessment of pollutant emissions and energy efficiency of four commercialized charcoal stoves with modified Chinese cooking stove protocol

Charcoal stove is widely used in the developing countries especially in Africa and Central America. Even reported to have a high impact on human health, stoves promoted in the related areas still mainly focus on fuel saving and little knowledge was reported for the stove performance in the field. This research evaluated four commercialized charcoal stoves with clay baseline stove using a modified Chinese cooking stove protocol that considered the local cooking habit to make the testing results more useful for the local stove promotion. The results showed that the thermal efficiency of tested charcoal stoves ranged from 38.7% to 47.5%, and the cooking power was around 640-1200 W. The CO emission factors of the improved stove had a 60% reduction compared with baseline stove. Different indicators reporting the same aspect of the stove were evaluated, and it suggested choosing the indicators according to the project requirements. Keywords: charcoal stove, energy efficiency, pollutant emissions, carbon dioxide emissions, testing protocol, cooking DOI: 10.25165/j.ijabe.20181102.3637 Citation: Zhang Y X, Hao J, Zhou Y G, Zhang Z X, Chen L, Dong R J. Assessment of pollutant emissions and energy efficiency of four commercialized charcoal stoves with modified Chinese cooking stove protocol. Int J Agric & Biol Eng, 2018; 11(2): 202–207.

Effects of zeolite application on grain yield, water use and nitrogen uptake of rice under alternate wetting and drying irrigation

With the increasing scarcity of water resources and growing population, the dual goal of saving irrigation water and increasing grain yield has become a major challenge in rice production around the world. A two-year lysimetric experiment was conducted to assess the effects of zeolite application (Z0: 0 and Z1: 15 t/hm2) and water regimes (W0: continuous flooding irrigation, W1: energy-controlled irrigation, W2: alternate wetting and drying irrigation) on grain yield, water use and total nitrogen uptake of rice. Zeolite addition to paddy field significantly increased grain yield, total N uptake, and water use efficiency (WUE), despite a negligible effect on amount of irrigation water used. Compared with W0, the separate use of W1 and W2 each considerably decreased irrigation water. However, W2-grown rice showed a significant decline in grain yield. In contrast, W1 showed comparable grain yield with W0, and achieved the highest WUE. Correlation analysis revealed that grain yield was significantly and positively correlated with effective panicles, spikelets per panicle, water consumption, and total N uptake. It is concluded that the combination of zeolite application at the rate of 15 t/hm2 and energy-controlled irrigation could be recommended to benefit farmers by reducing irrigation water while improving grain yield on a clay loam soil. Keywords: zeolite, alternate wetting and drying irrigation, rice, yield, water use efficiency DOI: 10.25165/j.ijabe.20181101.3064 Citation: Zheng J L, Chen T T, Xia G M, Chen W, Liu G Y, Chi D C. Effects of zeolite application on grain yield, water use and nitrogen uptake of rice under alternate wetting and drying irrigation. Int J Agric & Biol Eng, 2018; 11(1): 157–164.

Geotechnical characteristics and consolidation properties of Tianjin marine clay

Tianjin, which is located on the west shore of the Bohai Sea, is part of China\'s Circum-Bohai-Sea Region, where very weak clay is deposited. From the 1970s to the early 21st century, Tianjin marine clay deposits have been the subject of numerous geotechnical investigations. Because of these deposits\' geological complexity, great depositional thickness, high water content, large void ratio, excessive settlement, and low shear strength, the geotechnical properties of Tianjin marine clay need to be summarized and evaluated based on various in situ and laboratory tests so that Tianjin can safely and economically sustain more infrastructure in the coming decades. In this study, the properties of Tianjin marine clay, especially its consolidation properties, are summarized, evaluated and discussed. The focus is on establishing correlations between the geotechnical property indexes and mechanical parameters of Tianjin marine clay. These correlations include the correlations between the water content and the void ratio, the depth and the undrained shear strength, the liquid limit and the compression index, the tip resistance and the constrained modulus, the plasticity index and the ratio of undrained shear strength and the preconsolidation pressure. In addition, the primary consolidation properties of Tianjin marine clay, such as the intrinsic compression line (ICL), sedimentation compression line (SCL), compression index, Cc, coefficient of consolidation, Cv, and hydraulic conductivity change index, Ckv, are evaluated and discussed. A secondary consolidation property, i.e., the secondary compression index, Ca, is also investigated, and the results show that the ratio of Ca/Cc for Tianjin marine clay can be used to calculate Ca in secondary consolidation settlement predictions.

Effect of performance method of sand compaction piles on the mechanical behavior of reinforced soft clay

Sand Compaction Piles (SCPs) are constructed by feeding and compacting sand into soft clay ground. Sand piles have been installed with irregular cross-sectional shapes, and mixtures of both sand and clay, which violate the design requirement of circular shape according to the replacement area ratio due to various factors, including side flow pressure. Therefore, design assumptions cannot be satisfied according to the conditions of the ground and construction and the replacement area ratio. Two case histories were collected, examined, and interpreted in order to study the effect of the shape of SCPs. The effects of the distortion of SCP shape and the mixture of sand and clay were studied with the results of large direct shear tests. The design internal friction angle was secured with the irregular cross-sectional sand piles regardless of the replacement area ratio. The design internal friction angle was secured regardless of mixed condition when the mixture of sand and clay was higher than the replacement area ratio of 65%. Therefore, systematic construction management is recommended with a replacement area ratio below 65%.

Reuse of dredged sediments as pavement materials by cement kiln dust and lime treatment

This paper presents an investigation on the properties of two types of cement kiln dust (CKD)-stabilized dredged sediments, silt and clay with a comparison to hydrated lime stabilization. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted to examine the optimal stabilizer content and classify the type of highway material. A strength development model of treated dredged sediments was performed. The influences of various stabilizer types and sediment types on UCS were interpreted with the aid of microstructural observations, including X-ray diffraction and scanning electron microscopy analysis. The results of the tests revealed that 6% of lime by dry weight can be suggested as optimal content for the improvement of clay and silt as selected materials. For CKD-stabilized sediment as soil cement subbase material, the use of 8% CKD was suggested as optimal content for clay, whereas 6% CKD was recommended for silt; the overall CBR value agreed with the UCS test. The reaction products calcium silicate hydrate and ettringite are the controlling mechanisms for the mechanical performance of CKD-stabilized sediments, whereas calcium aluminate hydrate is the control for lime-stabilized sediments. These results will contribute to the use of CKD as a sustainable and novel stabilizer for lime in highway material applications.