Alojzy Szymański

Environmental and Geotechnical Assessment of the Steel Slags as a Material for Road Structure

Slags are the final solid wastes from the steel industry. Their production from waste and associated materials is a proper implementation of the basic objectives and principles of the waste management. This study aims to investigate the chemical and selected significant geotechnical parameters of steel slag as the alternative materials used in road construction. These investigations are strongly desired for successful application in engineering. Young’s modules E, and resilient modules Mr showed that their values corresponding with requirements for subbase (principal or auxiliary) and riding surface as well. Tested mechanical properties were conducted in soaked and un-soaked (optimal moisture content) conditions. The designated high content of chromium and zinc are strongly associated with the internal crystal structure of steel slag. The results do not lead to threats when they are applied in roads’ structures. Mechanical characterization was obtained by performing California bearing ratio (CBR) tests for steel slag in fixed compaction and moisture content conditions. Moreover, cyclic loading of steel slag was conducted with the application of cyclic California bearing ratio (cCBR) apparatus to characterization of this material as a controlled low-strength material. Finally, field studies that consist of static load plate VSS tests were presented.

Deformation Behavior of Recycled Concrete Aggregate during Cyclic and Dynamic Loading Laboratory Tests

Recycled concrete aggregate (RCA) is a relatively new construction material, whose applications can replace natural aggregates. To do so, extensive studies on its mechanical behavior and deformation characteristics are still necessary. RCA is currently used as a subbase material in the construction of roads, which are subject to high settlements due to traffic loading. The deformation characteristics of RCA must, therefore, be established to find the possible fatigue and damage behavior for this new material. In this article, a series of triaxial cyclic loading and resonant column tests is used to characterize fatigue in RCA as a function of applied deviator stress after long-term cyclic loading. A description of the shakedown phenomenon occurring in the RCA and calculations of its resilient modulus (Mr) as a function of fatigue are also presented. Test result analysis with the stress-life method on the Wohler S-N diagram shows the RCA behavior in accordance with the Basquin law.

Effect of Time on Dynamic Shear Modulus of Selected Cohesive Soil of One Section of Express Way No. S2 in Warsaw

Several researches published comprehensive reports on dynamic soil properties of cohesive soils, in which many of them outlined, i.e., key factors affecting the dynamic shear modulus. For cohesive soils, the modulus at small strains (g < 10t-3 %) is, first of all, a function of void ratio and effective confining stress. For clays, however, secondary time effects and clay mineralogy (fabric and structure) also appear to be important. The influence of confinement of laboratory-prepared as well as naturally deposited clays consists in an increase of shear modulus logarithmically as a function of time. In this paper, the effect of duration of the various confining pressures on dynamic shear modulus (G) of selected cohesive soils from Warsaw area was evaluated. Shear modulus was determined on the basis of resonant column tests, at low and high shearing strain amplitudes. It is shown that the calculated shear modulus is time-dependent; during approximately first 1000 minutes of consolidation, the moduli increased by almost 50%. Moreover, it is characterized by two phases: an initial one results from primary consolidation and a second one, which occurs after the end of primary consolidation, herein about 16-17 hours, and is called “long-term time effect”. This effect was found also for modulus at higher shearing strains (γ > 103%, e.g., 3 × 103%, 5 × 103%, 8 × 103%, 2 × 103%).

Determination of the Resilient modulus MR for the lime stabilized clay obtained from the repeated loading CBR tests

Abstract Determination of the Resilient modulusMR for the lime stabilized clay obtained from therepeated loading CBR tests. The main aim of this paper is to prove that CBR repeated test is useful to give an adequate like unconfi ned cyclic triaxial test parameters for design the pavement and subgrade soils. That parameter is the Resilient modulus (MR) which is the elastic modulus based on the recoverable strain under repeated load. Resilient modulus (MR), is an important parameter which characterizes the subgrade’s ability to withstand repetitive stresses under traffic loadings. The 1993 AASHTO guide for design of flexible pavements recommends the use of MR. The additional aim is connected with the concept of sustainable development. For many countries, where resources are at premium, it is very important that stabilized local soil can be used for road construction. For ensuring that stabilized clay can be used for pavement material standard compaction, CBR and repeated CBR tests were performed. In that paper parameter MRof the subgrade lime stabilized clay soil by laboratory CBR repeated test were determined using for calculation formulas from triaxial cyclic test. Based on AASHTO empirical equation the static CBR values using back analysis was also calculated. Finally both values of CBR determined and calculated were compared. Streszczenie Wyznaczanie modułu sprężystościMR w warunkach cyklicznego obciążania z badańpowtarzalnego CBR dla glin stabilizowanychwapnem. Głównym celem niniejszej pracy jest wykazanie, że badanie CBR w warunkach powtarzalnego obciążania jest wiarygodnym testem do wyznaczania parametrów sprężystości podłoża gruntowego. Parametry te są następnie wykorzystywane do projektowania podbudowy i ulepszonego podłoża gruntowego. Jednym z parametrów jest powtarzalny moduł sprężystości (MR) który opisuje odkształcenia sprężyste powstałe w wyniku cyklicznych obciążeń gruntu. Powtarzalny moduł sprężystości MR, jest ważnym parametrem, który charakteryzuje zdolność podbudowy do odkształceń w wyniku powstających naprężeń od obciążenia ruchem drogowym. Podręcznik AASHTO 1993 do projektowania elastycznych nawierzchni zaleca stosowanie MR. Celem artykułu jest także podjęcie problemu zasad zrównoważonego rozwoju. W wielu krajach, w których źródła odpowiednich kruszyw są oddalone od miejsca budowy, bardzo ważnym staje się wykorzystanie materiałów miejscowych poddanych zabiegom stabilizacyjnym. W celu potwierdzenia korzystnego wpływu stabilizacji na grunty spoiste o niekorzystnych parametrach wyjściowych wykonano badania CBR w warunkach statycznego obciążania i powtarzane badania CBR. W artykule wyznaczono parametr MRdla gliny piaszczystej stabilizowanej wapnem hydratyzowanym za pomocą badania powtarzalnego CBR przy zastosowaniu równań opracowanych dla interpretacji badań trójosiowego ściskania w warunkach cyklicznego obciążenia. Na podstawie równania empirycznego AASHTO wyznaczono również wartości CBR a także wykorzystano analizę wsteczną wyznaczenia wartości CBR z otrzymanych z badań wartości MR. W analizie wyników badań wartości te zostały ze sobą porównane wraz z komentarzem uzyskanych zależności.

Estimation of Flow Characteristics in Peat

This paper presents the behavior of the soft subsoil under structures such as embankment dams, particularly tailing dams which are nowadays usually placed in swampy areas often dominated by organic soils, such as peat. Structures construction on soft organic soils makes it necessary to calculate subsoil deformations with special consideration of the water flow. Constructions of embankments on soft organic soils cause many problems because of their specific properties. The organic soils, such as peat, are characterized by high porosity and low shear strength as well as high initial permeability which decreases during consolidation. In the deformation process of soil skeleton under loading the porosity decreases and causes changes of flow characteristics. Therefore, the water flow characteristics are very important to be considered in predicting and calculating the subsoil deformation under load. The specific behavior of soft subsoil demands estimation reliability of the flow characteristics. Therefore in the statistical analysis suitable statistical methods and proper measures in laboratory tests should be used. Several statistical functions have been applied to analyze the flow-pump test data in order to provide a correct estimation of flow characteristics in soft soils. In this paper, the results of water flow characteristics obtained in laboratory tests and the estimation of flow characteristics in soft organic soils are presented.

Impact of the stabilization of compacted cohesive soil – sandy clay on yield criterion improvement

Abstract Impact of the stabilization of compacted cohesive soil - sandy clay on yield criterion improvement. Soft soils, exhibiting low strength properties in the case of external load, require improvement. Chemical stabilization is easy in preparing and presents very good results in improving mechanical properties. In this paper, results of CBR and unconfined compressive strength test are presented for cohesive soil - sandy clay. Stabilization medium was Reymix, which is a cement derivative. Conducted tests define the characteristics of mechanical properties improvement and estimate yield criterion for stabilized soil during the time of stabilization, which is different for non-stabilized soils Streszczenie Wpływ stabilizacji zagęszczonego gruntu spoistego - iłu piaszczystego na wzrost granicy sprężystości. Grunty słabe, które przejawiają niewielką wytrzymałość mechaniczną na obciążenia zewnętrzne, wymagają wzmocnienia. Stabilizacja chemiczna jest łatwa w wykonaniu i daje bardzo dobre wyniki wzrostu właściwości mechanicznych. W artykule przedstawiono wyniki badania CBR oraz jednoosiowego ściskania gruntu spoistego - iłu piaszczystego ulepszonego za pomocą preparatu Reymix, który jest pochodną cementu. Przeprowadzone badania miały na celu określenie charakterystyki poprawy właściwości mechanicznych oraz wyznaczenie dla stabilizowanego gruntu granicy sprężystości, która jest inna niż w przypadku gruntów niestabilizowanych

Chapter 3 Laboratory investigations

Publisher Summary This chapter discusses the laboratory investigations. The common laboratory tests and equipments used for soft mineral soils can also be used for most organic soils. One condition for laboratory tests to be relevant to the field conditions for which the results are applied is that undisturbed and representative samples can be brought into the laboratory and mounted in the testing equipment. Particularly for peats, special samplers have to be used, as well as special trimming and mounting techniques. For fibrous and pseudo fibrous peats many of the common laboratory tests are not relevant. These soil types also often require larger specimens than usual to be tested and special apparatus, such as the compressiometer, to be used rather than ordinary oedometers. The initial ocular inspection and the very simple tests, with alkali extraction and lowering of samples into hydrochloric acid, required for preliminary soil classification, may be carried out in the field. In the laboratory, further quantitative analyses are carried out to enable a more precise classification and to give additional basic data.

Repeated Loading of Cohesive Soil – Shakedown Theory in Undrained Conditions

Abstract The development of industry and application of new production techniques could bring about extraordinary problems that have been neglected. One of these challenges in terms of soil mechanics is high frequency cyclic loading. Well constructed foundation may reduce this troublesome phenomenon but excluding it is usually uneconomic. In this paper, shakedown theory assumptions were studied. Cyclically loaded soils behave in various ways depending on the applied stress rate. Common cohesive soils in Poland, i.e., sandy-silty clays are problematic and understanding of their behaviour in various conditions is desired. In order to study repeated loading of this material, cyclic triaxial test were carried out. Cyclic loading tests were conducted also in one way compression. These methods in small strain regime allow permanent strain increment analysis with resilient response after numerous cycles. This behaviour was subsequently exploited in the study of shakedown theory. This paper contains some conclusions concerning the above-mentioned theory.

Small strain stiffness in overconsolidated Pliocene clays

Abstract Small strain stiffness in overconsolidated Pliocene clays. A huge development of technical infrastructure, including the construction of many high-rise buildings, roads, railroads and extension of subway lines, took place over the recent years in Poland. Therefore, numerous planned investment projects require geotechnical data documenting the variation of soil parameters found in the subsoil. The shear wave velocity is one of the most important input parameters to represent the stiffness of the soil deposits. This paper focuses on the methods and devices using measurements of the shear wave velocity to estimate the initial shear modulus in cohesive soil. It is preferable to measure VS by in situ wave propagation tests, however it is often economically not feasible in all regions of Poland. Hence, a reliable correlation between shear wave velocity and parameters measured in triaxial cell or static penetration parameters would be a considerable advantage. This study shows results obtained from the bender elements tests and field techniques - seismic cone penetration test and seismic flat dilatometer, performed on overconsolidated cohesive soils in Warsaw. On the basis of the test results possible correlations between shear wave velocity (initial shear modulus), mean effective stress and void ratio are considered and four original empirical relationships are proposed. Moreover, the proposed formulas by two different techniques using triaxial apparatus and also RCPT cone were examined. The proposed formulas show a reasonable agreement with direct shear wave velocity profiles for clays and might be incorporated into routine laboratory and field practice

The analysis of consolidation in organic soils

The analysis of consolidation in organic soils This paper is devoted to the specific difficulties connected to construction on problematic soils. Different type of structures like: road embankments, flood control levees, dykes and dams are often located in soft subsoil areas, which consists mainly of peat, calcareous soil with a very high content of calcium carbonate and other high plasticity organic and no organic soils. These soils can be characterized as highly deformable with low initial shear strength and an insufficient bearing capacity. Soft soils show a large deformation, both vertically and horizontally, under load. The settlements often appear very quickly and can also continue for a long time. The consolidation process consists here of two main stages: primary settlement and secondary (and tertiary) settlement (creep). It is essential to have a good quality description of physical and mechanical properties of soil before the calculation and construction stage. For calculations of each stage of settlement the different physical and mechanical parameters of problematic soil are applied. In this paper the analysis of organic soils deformation process is presented. The deformation characteristics were defined on the basis of laboratory tests results. Soil investigations were performed on peat samples taken from test site located in Olsztyn region. Laboratory test of physical properties and consolidation tests in oedometer were carried out. Based on laboratory test results the empirical relationships between stress and deformation as well as stress and time were elaborated in order to describe the primary consolidation in organic soils. Analiza procesu konsolidacji w gruntach organicznych Artykuł jest poświęcony szczególnym trudnościom związanym z posadowieniem konstrukcji na gruntach słabonośnych. Różne rodzaje budowli m.in. nasypy drogowe, wały przeciwpowodziowe, tamy i zapory są często lokalizowane na gruntach słabych, składających się zwykle z torfu oraz gytii o dużej zawartości węglanu wapnia oraz innych, wysoce plastycznych organicznych bądź nieorganicznych gruntów. Omawiane grunty charakteryzuje wysoka odkształcalność przy małej początkowej wartości wytrzymałości na ścinanie. Ponadto, pod obciążeniem wykazują one duże deformacje, zarówno pionowe, jak i poziome. Osiadania pojawiają się szybko, ale mogą trwać przez dłuższy czas. Proces konsolidacji składa się z dwóch głównych etapów: osiadań natychmiastowych oraz osiadań konsolidacyjnych (pełzanie). Istotny jest zatem właściwy opis fizycznych oraz mechanicznych właściwości tych gruntów, wykorzystywany następnie przy obliczeniach i projektowaniu konstrukcji. W artykule przedstawiono analizę procesu konsolidacji gruntów organicznych, opartą na wynikach badań laboratoryjnych. Badania te przeprowadzono na próbkach torfu pobranych z poligonu doświadczalnego uczelni zlokalizowanego w okolicach Olsztyna. Badania laboratoryjne opierały się na analizie fizycznych właściwości gruntów oraz testach konsolidacyjnych, wykonanych w edometrach. Uzyskano empiryczne zależności pomiędzy naprężeniem oraz odkształceniem, jak również naprężeniem i czasem, które posłużyły do opisu konsolidacji pierwotnej w gruntach organicznych.