Earthen architecture largely supports the concept of sustainable building. In the seismically active area of eastern Croatia, there is a large number of rammed earth houses, many of which are over ...100 years old. All these houses were built using empirical knowledge, i.e., without applying national design standards. In order to support the preservation of ethnic villages and traditional rammed earth houses, a field survey was conducted. Parts of the walls of traditional rammed earth houses were collected, and the material was thoroughly analyzed. Samples of rammed earth were reproduced, and tests were carried out with the aim of determining the shear strength to subsequently determine the seismic behavior of Croatian traditional earthen architecture. This paper presents the results of shear strength tests on samples with different particle size distributions, lime content, the straw of different cereals but also hemp fibers. An increase in shear strength was observed with the addition of natural fibers to the samples.
Earthen architecture has a significant share in the world’s fund of both residential architecture and cultural heritage. It provides a home to more than half of the world’s population and can be ...found in seismically active areas. Empirically acquired knowledge on building with rammed earth (RE) has usually been passed down from generation to generation by word of mouth, with no written scientific grant for the load-bearing capacity and resistance of structural elements. Today, many countries still do not have standards for the design of RE structures. In the development of new as well as existing design standards, the results of experimental research play a significant role. The focus of this study was on unstabilized RE, which is locally available material with low embodied energy. This paper elaborates experimental campaigns, within which meticulous techniques were employed to provide new knowledge on RE for use in earthquake-prone areas. Furthermore, this paper includes: (i) ranges of values of mechanical properties determined on RE specimens from all over the world; (ii) a comparative summary of experimental research conducted on walls and buildings to assess their seismic performance; (iii) an overview of standards and testing methods used in experiments; and (iv) recommendations for further research.
The aim of this research was to better understand the influence of adding waste rubber in cement bound aggregate (CBA) by testing both the unconfined and triaxial stress state. CBA with waste rubber ...was tested in this manner aiming to analyse influence of the confining pressure on the material behaviour. The results indicate that adding 20% rubber to a high cement content mix can assimilate the high stiffness caused by the high cement paste content, resulting in a mixture with increased cement paste content to facilitate in situ compaction. Additionally, a low confining pressure of 40 kPa has the most impact on the elastic properties/stiffness and it would be more appropriate to measure the CBA elasticity modulus with moderate lateral (confining) pressure. Finally, the practical implication of this research is that, in pavement mechanistic-empirical design, a correction of the measured uniaxial static modulus of elasticity by 10-15% should be adopted.
Rammed earth buildings constitute a large part of the housing stock in rural areas. Although these houses are recognized as a cultural heritage, detailed analyses of their architectural features, ...geometric parameters crucial for structural stability, and soil properties used for their construction have not yet been carried out in Croatia. The aim of this study is to collect basic data on the architectural features and material properties of rammed earth walls through field research in Croatia. These data are crucial for both numerical and experimental studies to improve the understanding of the structural behavior of rammed earth houses. Data were obtained through field research and a detailed survey of 22 houses. The houses were analyzed, samples of the rammed earth walls were collected, and their properties were tested in the laboratory. This study contributes to a better understanding of regional building practices and provides data that will enable us to identify the causes of damage in future studies and to select rehabilitation measures to preserve the authentic symbols of cultural heritage.
This paper presents the potential energy savings and how to achieve sustainability by predicting the temperature of aggregate stockpiles in the production process of asphalt mixtures. A possible way ...to achieve energy efficiency and therefore sustainability is to preheat the mineral mixture, i.e. the aggregate, before it enters the production process in the asphalt mixing plant, thus resulting in lower energy consumption per ton of asphalt. The main objective of the conducted research was to develop and test an artificial neural network (ANN) model and analyse the influence of three independent variables (hour in the day, season, air temperature) on the one dependent variable (temperature of the mineral mixture). The impact of the observed independent variables on the temperature of the mineral mixture is analysed in a standard uncovered aggregate stockpile and in a solar aggregate stockpile. From the obtained modelling results, it can be concluded that it is possible to successfully use ANN in the process of predicting the temperature of aggregate stockpiles in the processes of aggregate production and storage as part of the whole production process of asphalt mixtures.
•Different aggregate stockpile deposit methods influence stockpile temperatures.•Higher aggregate temperature lowers energy consumption of produced asphalt.•Aggregate deposit method management makes production process more energy efficient.
In eastern Croatia rammed earth houses were traditionally built in the past. The choice of suitable soil for building rammed earth houses depends on several soil properties. Moreover, since there are ...no standards or recommendations for construction of rammed earth houses in Croatia, the construction and renovation of such houses is almost non-existent nowadays. With the aim of forming detailed recommendations for eastern Croatia area in near future, soil samples were collected from existing houses to test the physical properties of the soil. Obtained results showed that Atterberg limits are within the limits of the recommended values and published results in the literature, while particle size distribution differs from most recommendations and published results.
In road base layers, geogrids assume the reinforcement or stabilization function where good interaction between geogrid and unbound base material is important. The cyclic triaxial test can be used ...for analysing interaction between geogrid and unbound base material. The paper includes an overview of research where cyclic triaxial test is primarily used for assessing the influence of parameters such as geogrid stiffness, geometry and aperture size, position and number of geogrid layers, on the interaction with the base layer material. The cyclic triaxial test can be used to determine contribution the geogrid application in non-cohesive materials has on the reduction of permanent deformations.
The analysis of water seepage below the model’s foundation of hydrotechnical object is conducted in the paper. A physical model of gravitational dam is made with the aim to visualize seepage through ...the ground below the dam. The model is made at the laboratory of the Faculty of Civil Engineering and Architecture in Osijek. The aim of the paper is to analyze the influence of the hydraulic gradient on seepage domain deformation, as well as to study the effect of different engineering measures on the decrease of hydraulic gradient. Four measurements were conducted which were mutually distinguished by the shape of the dam model, i.e. the foundation sheet. The first part of the paper is based on the assessment of measurement variants, i.e. engineering solutions used for the reduction of the seepage part of the buoyancy and seepage flow. The second part of the paper is dedicated to adoption of different models in the analysis of groundwater seepage below the object. Values related to seepage flow as well as buoyancy and pressure distribution below the foundation sheet were analyzed. Graphical, numerical, and approximate methods of analysis were used
U nosivim slojevima kolničke konstrukcije geomreže imaju funkcije ojačanja ili stabilizacije, pri čemu je važna dobra interakcija geomreže i nekoherentnog materijala nosivog sloja. Za ispitivanje ...interakcije geomreže i materijala nosivih slojeva kolničkih konstrukcija može se primijeniti pokus cikličkim troosnim posmikom. Rad obuhvaća pregled istraživanja primjene cikličkog troosnog posmika posebice tijekom ocjenjivanja utjecaja parametara kao što su krutost, geometrija i veličina otvora, položaj i broj slojeva geomreže na interakciju s materijalom nosivog sloja. Ocjenjuje se da se cikličkim troosnim posmikom može utvrditi doprinos primjene geomreža u nekoherentnim materijalima u vidu smanjenja trajnih deformacija.
Constructing embankments on compressible foundation soil normally requires soil improvement measures to reduce the amount and duration of settlement. In the most difficult cases, the soil is improved ...by using pile foundations. When constructing pile foundations, it is necessary to ensure efficient load transfer from the embankment to the piles, which can be achieved using reinforced soil construction with geosynthetics as reinforcement material. In this paper, we compare the calculations of a bearing capacity of such a platform according to the British and the German standards on the example of a level crossing over a railway line. We describe other calculation methods, critically reviewing the fundamental mechanisms of the reinforcement effects in the calculations.
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