Engineering properties for high kitchen waste content municipal solid waste

Engineering properties of municipal solid waste （MSW） depend largely on the waste＇s initial compositionand degree of degradation. MSWs in developing countries usually have a high kitchen waste content（called HKWC MSW）. After comparing and analyzing the laboratory and field test results of physicalcomposition, hydraulic properties, gas generation and gas permeability, and mechanical properties forHKWC MSW and low kitchen waste content MSW （called LKWC MSW）, the following findings wereobtained： （1） HKWC MSW has a higher initial water content （IWC） than LKWC MSW, but the field capacitiesof decomposed HKWC and LKWC MSWs are similar; （2） the hydraulic conductivity and gaspermeability for HKWC MSW are both an order of magnitude smaller than those for LKWC MSW; （3）compared with LKWC MSW, HKWC MSW has a higher landfill gas （LFG） generation rate but a shorterduration and a lower potential capacity; （4） the primary compression feature for decomposed HKWCMSW is similar to that of decomposed LKWC MSW, but the compression induced by degradation ofHKWC MSW is greater than that of LKWC MSW; and （5） the shear strength of HKWC MSW changessignificantly with time and strain. Based on the differences of engineering properties between these twokinds of MSWs, the geo-environmental issues in HKWC MSW landfills were analyzed, including highleachate production, high leachate mounds, low LFG collection efficiency, large settlement and slopestability problem, and corresponding advice for the management and design of HKWC MSW landfills wasrecommended.

Engineering properties and microstructure of expansive soil treated with nanographite powder

To reduce geological disasters caused by expansive soil,it is crucial to use a new type of modified material to rapidly improve soil strength instead of traditional soil improvement materials such as lime and cement.Nanographite powder(NGP)has excellent properties,such as high adsorption,conductivity,and lubrication,since it has the characteristics of small size,large specific surface area,and high surface energy.However,previous studies on the improvement of expansive soil with NGP are not processed enough.To study the improvement effect of NGP on expansive soil,non-load swelling ratio tests,consolidation tests,unconfined compressive strength tests,mercury injection tests,and micro-CT tests on expansive soil mixed with different NGP contents were performed.The results show that the non-load swelling ratio,mechanical properties,and porosity of expansive soil show some increasement after adding NGP.The strength of expansive soil reaches the maximum when the NGP content is 1.450%.The cumulative mercury volume and compressive strain of expansive soil reach the maximum with the 2.0%NGP content.Finally,the modification mechanism of swelling,compressibility,microstructure,and compressive strength of expansive soil by NGP is revealed.

Effect of textural characteristics on engineering properties of some sedimentary rocks

As it is commonly known,the estimation of physical and mechanical characteristics of rocks is very important issue in various geotechnical projects.The characteristics are mainly influenced by the microfabric-texture features of rocks.In this research,dry unit weight,effective porosity,point load index,Schmidt rebound hardness,uniaxial compressive strength,and texture coefficient were measured with the aim of correlating the physical and mechanical properties to the texture coefficient.For this purpose,a comprehensive laboratory testing program was conducted after collecting twenty sedimentary block samples including nine limestones and eleven mudstones,taken from Kalidromo(central Greece)in accordance with ASTM and ISRM standards.Also,mineralogical and petrographic properties,textural characteristics as well as X-ray diffractions were studied and the obtained results were statistically described and analysed.The maximum and minimum values of the texture coefficient were 0.13 and 0.50,respectively.The highest value was obtained for the rocks with a large amount of grains.Regression analyses were used to investigate the relationships between the texture coefficient and the engineering properties.Thus,empirical equations were developed and because of the good determination coefficients,they showed that all of the engineering properties were well correlated to the texture coefficient.

Engineering Properties of Unstabilized Rammed Earth with Different Clay Contents

The physical and mechanical properties of unstabilized rammed earth with different clay contents were studied, which could provide a theoretical basis for the understanding of mechanical properties of unstabilized rammed earth and improve the construction design method and specification of RE buildings for sustainable development. The experimental results show that clay content has significant influences on the engineering properties of unstabilized rammed earth. For the fine-grained soil, the liquid limit, plastic limit and plasticity index increase gradually with the increase of the clay content. The influence of clay content on the optimum moisture content compared with the maximum dry density is more significant. The mechanical properties of unstabilized rammed earth are significantly affected by the clay content. There exist good linear relationships, which can be used for the mutual verification or calculation among the mechanical properties. An empirical model of unconfined compression strength with the FA/CA ratio as the main parameter is established, and the UCS may obtain the maximum with a FA/CA ratio of 5.77.

Ability of rotary compactor in compacting consistent slabs and effect of rotary compaction on engineering properties of stone mastic asphalt mixtures

A new automatic rotary compactor and its abilities in compacting stone mastic asphalt （SMA） are presented. Following an overview of the rotary compactor and the compaction procedure, it is demonstrated that the rotary compactor is able to produce uniform slabs with the desired thickness of 65 mm all over around. Furthermore, 132 cored samples from the rotary compactor had been compacted uniformly with approximately 4% optimum air void content. In addition, performance tests results indicate that the rotary compactor produces asphalt mixturures with the requirements of resilient modulus, Marshall stability and flow. A weight factor was introduced for each fraction of aggregates in the degradation analysis to compensate the crushing effect of aggregates during mixing and compacting.

Some Engineering Properties of Sunflower Seed and Its Kernel

Some engineering properties of sunflower seed and its kernel, Shahroodi variety as a case study, were investigated at various moisture content levels （3-14% d.b.） for three size categories （large, medium and small）. With increase of moisture content from 3 to 14% d.b., all the main dimensions （length, width and thickness）, geometric mean diameter, porosity, true density, terminal velocity and static coefficient of friction increased while bulk density and rupture force for both sunflower seed and its kernel decreased for all size categories. The results showed that the highest value of static coefficient of friction for both seed and kernel was on the rubber surface, followed by plywood, polyethylene, galvanized iron, and finally aluminium surfaces. The seeds required less compressive force to dehull when loaded under the horizontal as compared to the vertical orientation. But for kernels, the trend was the opposite. Also, the compressive forces needed to initiate rupture of sunflower seed hulls were higher （47.1-94.72 N） than those required to rupture the kernel （8.5-13.4 N） in both orientations.

Geological and Engineering Properties of Granite Rocks from Aqaba Area, South Jordan

Jordanian granitic rocks (JG) are highly distributed and available in huge quantities in south Jordan, Aqaba area. Granite in south Jordan (JG) is belonging to Aqaba granite complex. This study has been carried out to investigate geological and engineering properties of JG from Aqaba vicinity, south Jordan, in addition to identify and classify the different granitic rocks. 27 random samples of JG were collected from different quarries in three locations from the study area to investigate their characterization. Engineering properties of JG were tested and investigated using ultra sonic velocity test, abrasion test, flexural strength, specific gravity test, and compressive strength test. Engineering tests results show that JG has metal disk abrasion less than 21 mm, flexural strength of 16.9 Mpa, average dry specific gravity of 2.69 and very low absorption while the compressive strength results range between 60 to 90 Mpa. The results show that the engineering characterization of JG is complying with local and international specifications and standards used for classifying the decorative and building granite stones.

Engineering Properties of Expansive Soil

The components of expansive soil were analyzed with EDAX, and it is shown that the main contents of expansive soil in the northern Hubei have some significant effects on engineering properties of expansive soil. Furthermore, the soil modified by lime has an obvious increase of Ca^(2+) and an improvement of connections between granules so as to reduce the expansibility and contractility of soil. And it also has a better effect on the modified expansive soil than the one modified by pulverized fuel ash.

Analysis on the development of chemically-improved soil in railway engineering

Purpose-Explore the development trend of chemically-improved soil in railway engineering.Design/methodology/approach–In this paper,the technical standards home and abroad were analyzed.Laboratory test,field test and monitoring were carried out.Findings–The performance design system of the chemically-improved soil should be established.Originality/value–On the basis of the performance design,the test methods and standards for various properties of chemically-improved soil should be established to evaluate the improvement effect and control the engineering quality.

Impact of soil compaction on the engineering properties of potato tubers

A study on a 30 hm2 field was conducted to assess the variability in soil compaction and to investigate its effect on the engineering properties of potato tubers in terms of tuber shape and key dimensions(length,width and thickness)and resistance to penetration,rupture and shear forces.Three soil compaction levels were spatially correlated with the engineering properties of potato tubers through linear regression and ANOVA test.The three compaction levels included a low level(C1)ranging between 1.2-1.9 MPa,a medium level(C2)with compaction levels between 2.0-2.3 MPa and a high level(C3)ranging between 2.4-2.9 MPa.Results revealed that there were no significant changes in the key tuber dimensions corresponding to the variability in soil compaction.However,inverse linear relationships were observed between soil compaction and the key tuber dimensions with R2 values of 77%,97%and 96%for length,width and thickness,respectively.Similarly,the soil compaction was shown to have no effect on the tuber resistance to compression and shear force.In contrast,the tuber resistance to penetration was significantly affected by soil compaction(p>F=0.0012).

Calcium phosphate cements for bone engineering and their biological properties

Calcium phosphate cements （CPCs） are frequently used to repair bone defects. Since their discovery in the 1980s, extensive research has been conducted to improve their properties, and emerging evidence supports their increased application in bone tissue engineering. Much effort has been made to enhance the biological performance of CPCs, including their biocompatibility, osteoconductivity, osteoinductivity, biodegradability, bioactivity, and interactions with cells. This review article focuses on the major recent developments in CPCs, including 3D printing, injectability, stem cell delivery, growth factor and drug delivery, and pre- vascularization of CPC scaffolds via co-culture and tri-culture techniques to enhance angiogenesis and osteogenesis.

State of the art review on physiochemical and engineering characteristics of fly ash and its applications

The focus of this study is to critically review the physiochemical and engineering properties of the fly ash and its applications in various fields.The utilization of fly ash has become a widespread area,but the amount of utilization is still a serious issue.It has many beneficial qualities(such as pozzolanic property,fineness,spherical shape,lightweight,etc.),which enhance its properties and make it suitable for its utilization as a new construction material.For the bulk utilization of fly ash,it should be employed in the areas independent of any other parameters.So that,the disposal problem can be reduced significantly.The knowledge of its physiochemical characteristic helps in the judgment of appropriate fly ash for any particular type of work.Fly ash can be utilized in other areas such as asphalt concrete,geopolymer concrete,ground improvement,agricultural sector,roller compacted concrete,brick,etc.that will reduce the existing ashes,and also the disposal problem can be solved appreciably.The implementation of fly ash must be avoided below the natural ground water level and below 4°C temperature conditions.

Rock engineering property of the high-steep open-pit slope and its stability

According to the rock engineering property and stability of high-steep open-pitslopes, various factors were collected on the basis of rock engineering system (RSE) theory,and the interaction matrix of stability evaluation was established.Then, the stabilityevaluation index (S_p) of the slope was put forward.Ranges of the S_p value and the correspondingstable state were given on the basis of thirty-six samples.It is found that the followingrelationships exist: unstable (easy landslide): S_p<-0.20; mid-stable (may be landslide):-0.20<S_p<0.63; stable (no landslide): S_p>0.63.Finally, the stability evaluation indexwas applied on the high-steep open-pit slope of one mine.Analysis results and monitoringdata indicate that the index meets the necessity of the property of slope engineering, and ithas an important engineering purpose for landslide forecasting of high-steep slopes.

Model investigation of the low-carbon MgO-treated soil foundation based on CO_(2) overall carbonation

The overall carbonation of MgO-admixed soil provides not only an efficient and environmentally friendly technique for improving soft ground but also a permanently safe solution for CO_(2) sequestration.To evaluate the carbon sequestration potential and promote the carbonation application in soil improvement,a laboratory-scale model investigation is designed under pressurized carbonation considering the influences of MgO dosage and CO_(2) ventilation mode(way).The temperature,dynamic resilience modulus,and dynamic cone penetration(DCP)were tested to assess the carbonation treatment effect.The physical,strength,and microscopic tests were also undertaken to reveal the evolution mechanisms of CO_(2) migration in the MgO-carbonated foundation.The results indicate that the temperature peaks of MgO-treated foundation emerge at w20 h during hydration,but occur at a distance of 0e25 cm from the gas source within 6 h during carbonation.The dynamic resilience moduli of the model foundation increase by more than two times after carbonation and the DCP indices reduce dramatically.As the distance from the gas inlet increases,the bearing capacity,strength,and carbon sequestration decrease,whereas the moisture content increases.Compared to the end ventilation,the middle ventilation produces a higher carbonation degree and a wider carbonation area.The cementation and filling of nesquehonite and dypingite/hydromagnesite are verified to be critical factors for carbonation evolution and enhancing mechanical performances.Finally,the overall carbonation model is described schematically in three stages of CO_(2) migration.The outcomes would help to facilitate the practical application of CO_(2) sequestration in soil treatment.

Construction utilization of foamed waste glass

Foamed waste glass(FWG) material is newly developed for the purpose to utilize the waste glassware and other waste glass. FWG has a multi-porous structure that consists of continuous or discontinuous voids. Hence lightweight but considerable stiffness can be achieved. In the present study, the manufacture and engineering properties of FWG are introduced first. Then, the utilizations of FWG are investigated in laboratory tests and field tests. Some case studies on design and construction work are also reported here. Through these studies we know that the discontinuous void material can be utilized as a lightweight fill material, ground improvement material and lightweight aggregate for concrete. On the other hand, the continuous void material can be used as water holding material for the greening of ground slope and rooftop, and as clarification material for water.

Ancient Materials and Substitution Materials Used in Thai Historical Masonry Structure Preservation

The historical structures of Thailand are some of the most fascinating ancient sites in Asia.Their architectures reveal past cultures,traditions,knowledge,and expertise.Masonry materials are the major materials used to construct the historical structures in Thailand.One of the essential problem of Thai historical structure preservation is a shortage of engineering properties data for the structural stability assessment.Moreover,the in-depth engineering properties and the suitable substitution materials for Thai historical preservation are rarely found.Therefore,the engineering properties of the ancient masonry materials have to be explored together with the development of suitable substitute materials.This paper presents the physical and engineering properties of ancient materials and substitution materials for the preservation of Thailand’s historical structures.The ancient materials,including brick and mortar,are collected from historical places in the Bangkok and Ayutthaya Provinces.The physical and engineering properties of the masonry materials,such as the chemical composition,mineralogical composition,density,porosity,absorption,water vapor transmission,compressive strength,and modulus of elasticity,were evaluated in the laboratory.Fly ash was used as a pozzolanic material to partially replace the slaked lime to restore the historical mortar.The binder to sand ratio was controlled at 1:3 by weight.The slaked lime was substituted by fly ash at the rates of 10–30%by weight of binder.The engineering properties of the substitution mortars were also evaluated and compared with the ancient masonry materials.A masonry prism was also constructed to evaluate the compressive strength and the modulus of elasticity of the masonry structures.The physical and engineering properties of the ancient masonry materials obtained in this study can be included in a database for the preservation of Thailand’s historical masonry structures.The use of fly ash to partially replace the slaked lime could decrease the setting time and increase the compressive strength of historical repair mortar.The empirical equation obtained from this study could be used to predict the compressive strength of the masonry prisms of Thailand’s historical structures.

Utilization of Low-Alkalinity Cementitious Materials in Cemented Paste Backfill of Gold Mine Tailings

The purpose of this paper was to explore the possility of using low alkalinity cementitious materials as binders,in which ground blast furnace slag and fly ash acted as a partial replacement of ordinary Portland cement,and CaSO_(4),Na_(2)SO_(4),and CaO were used as a sulfate activator and alkali activated additives,to solidify gold mine tail-ings for preparation of a green,inexpensive cemented paste backill(CPB).For this target,the effects of cement/tailings ratio,superplasticizer dosage,solid content,tailings fineness on the mechanical properties of the CPB were inves tigated.Additionally,the hydration mechanism of the CPB was analyzed based on X-ray diffraction and scanning electron microscopy results.The results showed that the fuidity of the CPB slurry could be improved by adding polycarboxylic acid superplasticizer.The unconfined compressive strength(UCS)of the CPB specimens was increased with the increase of cement/tailings ratio and solid content.Under the same experi-mental conditions,the 28 d UCS of the CPB specimens was 3.8-4.9 times higher than that of ordinary Portland cement.The softening coefficient of the CPB specimens was increased with the increasing cement/tailings ratio,ranging from 0.83 to 0.92.The shrinkage rate of the CPB specimens was decreased from 0.70%to 0.54%with the increase of cement/tailings ratio from 1:12 to 1:4 The UCS of the full tailings CPB was the highest,followed by the fine tailings CPB specimens,and the UCS of the coarse tailings CPB specimens was the lowest.The low alka-linity binder was proved to be a promising material to improve the engineering performances of the CPB.The optimal mixing ratio is 1:6 cement/tailings ratio,0.15 wt% superplastizer dosage,and 70 wt%solid content.Pre-pared by this mixing ratio,the UCS values of the CPB after 3,7,and 28 d curing ages reached 1.85,5.87,and 9.16 MPa,respectively,which were suitable as CPB for the Zhaoyuan gold mine in terms of strength requirements.

Geotechnical behavior of the MSW in Tianziling landfill

The valley shaped Tianziling landfill of Hangzhou in China built in 1991 to dispose of municipal solid waste (MSW) was designed for a service life of 13 years. The problem of waste landfill slope stability and expansion must be considered from the geotechnical engineering point of view, for which purpose, it is necessary to understand the geotechnical properties of the MSW in the landfill, some of whose physical properties were measured by common geotechnical tests, such as those on unit weight, water content, organic matter content, specific gravity, coefficient of permeability, compressibility, etc. The mechanical properties were studied by direct shear test, triaxial compression test, and static and dynamic penetration tests. Some strength parameters for engineering analysis were obtained.

Study on ASTM Shear-loaded Adhesive Lap Joints

Finite element analyses and experiments are conducted to analyze the mechanical behavior of ASTM shear-loaded adhesive lap joints. Adhesive is characterized for the stress-strain relation by comparing the apparent shear-strain relations obtained from finite element analysis and experiments following ASTM D 5656 Standard. With the established stress-strain relation, two failure criteria using equivalent plastic strain and J-integral are adopted to predict the failure loads for joint specimens following ASTM D 5656 and ASTM D 3165 Standard, respectively. Good correlation is found between the finite element results and the experimental results. The strength of ASTM D 3165 specimens with debonding defects is also studied. Calculation results shows that experiment data following the standards provide only relative material constants, such as apparent shear modulus and strengths. Further investigation is required to find out the engineering properties needed for actual joint design. For the specimens with debonding defects, the locations of defects have great effects on their load bearing ability.

Tensile ductility improvement of AlSi9Cu1 alloy by chemical composition optimization

Diesel engines, characterized by higher breakout pressure and compression ratio in comparison with gasoline engines, require particularly elevated tensile properties for their engine parts. In order to maintain both high strength and high ductility in the cylinder head, i.e., to obtain higher percent elongation without further reducing the tensile strength, Al Si9Cu1 alloy was used to prepare the cylinder head in an aluminum diesel engine. At the same time, the effect of different modification elements, Na or Sr, and Fe content on the reduction of secondary dendrite arm spacing(SDAS) was discussed, and the design of T7 heat treatment parameters were analyzed in order to improve the tensile ductility. The result shows:(1) The SDAS is as small as 18±3 μm for the Sr modified alloy.(2) The percent elongation of the alloy with Sr modification increases by 66.7% and 42.9%, respectively, compared with the unmodified alloy and the alloy with Na modification.(3) Lower Fe content alloy(0.10%) gives good results in percent elongation compared to the alloy with higher Fe content(0.27%); in particular, after Sr modification and T7 heat treatment, the elongation of over 5% is obtained.