Hasil untuk "Highway engineering. Roads and pavements"

Roman Smolyanyuk, Serhii Khalin

Introduction. Traffic control devices, primarily traffic signs and road markings make the roadway environment intelligible to drivers and have a major impact on safety. Manual inspections remain the benchmark for compliance, but they are labour‑intensive, costly, and episodic, which creates long lag times between deterioration and remediation. Recent advances in computer vision and deep learning enable automated pipelines that detect, classify and assess the condition of signs using video and images, optionally supported by photometric measurements of retroreflectivity. Problem statement. Despite high accuracy on public benchmarks, deep models degrade in real‑world edge cases: fading, dirt, graffiti, occlusions by foliage, snow or fog, and strong off‑axis viewpoints. Moreover, condition assessment requires quantified metrics — colour difference, glyph legibility and contrast, geometric deformation and retroreflectivity — rather than a coarse «good / damaged» label. Purpose. To consolidate approaches for automated inspection, compare their strengths and limitations under realistic constraints, and outline an edge–cloud architecture that minimizes manual effort while meeting regulatory tolerances. Materials and methods. We consider a spectrum of methods — from color/shape rules and classical hand-crafted features (HOG-SVM, SIFT-SVM) to single-stage object detectors (YOLOv8, SSD), two-stage detectors (Faster R-CNN, Mask R-CNN), and multi-task as well as multimodal approaches that incorporate depth maps (LiDAR/stereo). For quantitative condition assessment, we describe conversion to the CIELAB color space after Gray-World or Shades-of-Grey white balancing, the use of physics-guided networks to estimate retroreflectivity, and the evaluation metrics employed (mAP for recognition, RMSE for condition regression, FPS on Jetson-NX). Results. Based on aggregated data, single- and two-stage deep detectors deliver mAP of 0.95 – 0.97, while multi-task/multimodal pipelines achieve the lowest error in condition estimation (RMSE 0.05 – 0.08). On edge devices, 18 – 35 fps is attainable (architecture-dependent), enabling on-device processing with subsequent offloading of candidate frames for heavy segmentation in the cloud. The proposed architecture combines a lightweight on-board YOLOv8-Nano detector (~28 fps) with cloud modules for segmentation and photometric analysis; contrastive pretraining on 20,000 unlabeled patches reduces labeling needs by ~60%, and an inexpensive solid-state LiDAR improves damage-class accuracy and enables tilt/roll measurement with ±2° precision.

Leonida Chaikovska, Liuda Panibratets, Serhii Stepanov et al.

Introduction. Bridges are important critical infrastructure facilities; they play a key role in economic development and ensure the security of regions and the state as a whole. During the period of martial law, bridges became an important element of the country's defense capability, as well as routes for humanitarian evacuation and export logistics. To make effective management decisions at the level of the State Agency for the Restoration and Development of Infrastructure of Ukraine in the field of bridge management, the Analytical Expert Bridge Management System (AESUM) software package is being implemented. Problem statement. In connection with the introduction of martial law in Ukraine, ensuring the proper functioning of the bridge sector has become of great social importance, since the availability of sustainable transport links allows to ensure the vital activity of the population and the functioning of the state under martial law. It is also important to improve the strategy of operation of transport facilities, taking into account the scientific and analytical apparatus of the AESUM software package. Objective. Implementation of an effective strategy for the operation of bridges on highways in order to plan financial resources for their repair and maintenance. Providing the general public with up-to-date statistical information on bridges from AESUM will be useful for scientific and practical purposes, and identifying certain analytical trends will allow to improve AESUM in terms of forming a strategy for the operation of transport facilities.

Zhaohui Liu, Shiqing Yu, You Huang et al.

Rigid-flexible composite pavement has gained significant popularity in recent decades. This paper provides a comprehensive review of the research progress concerning rigid-flexible composite pavement, aiming to promote its application and address key issues while identifying future directions. The design theory and methodology of rigid-flexible composite pavement are discussed, followed by a description of its structural and mechanical behavior characteristics. The load stress, temperature stress, and their interactive effects between the asphalt layer and the rigid base were analyzed. It is clarified that the asphalt layer serves a dual role as both a “functional layer” and a “structural layer”. Typical distresses of rigid-flexible composite pavement, which primarily occur in the asphalt layer, were discussed. These distresses include reflective cracking, top-down cracking, rutting, and compressive-shear failure. Generally, the integrity of the rigid base and the interlaminar bonding conditions significantly impact the performance and distress of the asphalt layer. The technology for enhancing the performance of rigid-flexible composite pavement is summarized in three aspects: asphalt layer properties, rigid base integrity, and interlaminar bonding condition. The study concludes that developing high-performance pavement materials based on their structural behaviors is an effective approach to improve the performance and durability of rigid-flexible composite pavement. The integrated design of structure and materials represents the future direction of road design.

Anatolii Tsynka, Serhii Illiash, Serhii Rybalchenko et al.

Introduction. This article considers the issue of improving the requirements for the operational condition of public highways and streets (hereinafter referred to as highways) and railway and tram crossings based on the analysis of current legal acts, regulatory documents, technical literature, which refers to the objects of standardization, taking into account the requirements for safety and environmental protection at all stages of the road life cycle, in particular operational maintenance. Problem Statement. A significant number of traffic accidents that occurred due to defects in the components of highways require improvement in the organization and conduct of inspections and surveys of highways with the establishment of compliance of a certain number of indicators with regulatory requirements. In addition, the resolution adopted by the UN General Assembly dated 31.08.2020 No. 74/299 «Improving road safety around the world» states that deaths and serious injuries as a result of road traffic accidents can in most cases be prevented on the basis of creating a safer highway infrastructure, which also contributes to the development of regulatory documents that establish modern technical requirements for the operational condition of highways Purpose. Ensuring safety and comfortable conditions for road users, increasing the durability of highways and establishing clear and unambiguous requirements for the operational maintenance of highways.

Iaroslav Iliyn, Serhii Misnichenko, Serhii Oksak et al.

Introduction. Mastic asphalt concrete is one of the oldest road construction materials used for road pavements. Problem Statement. Mastic asphalt concrete is a type of hot asphalt concrete, a feature of which is an increased amount of mineral powder and bitumen binder, due to which mastic mixtures can be placed in the road surface without compaction. Therefore, one of the main technological indicators of the quality of mastic asphalt mixtures is their fluidity. This indicator is one of the most important for designing the composition of the mastic asphalt mix, establishing the optimal amount of bitumen binder and setting the technological temperatures for preparing the mix at the plant and placing it in the road surface. Despite this, this indicator is not currently defined or standardized in the domestic road industry. The purpose. The aim of the study was to review the method for determining the plasticity of mastic asphalt mixtures based on the immersion depth of the test rod, as well as to establish the possibility and feasibility of its use for assessing the quality of mastic mixtures. Materials and methods. The object of study is the method for determining the plasticity of mastic asphalt mixtures based on the immersion depth of the test rod, which is used in European countries to select the composition of mastic mixtures and establish the optimal temperature conditions for their manufacture and paving. The method of determining plasticity was tested on a mastic asphalt mixture LABS-10 made on BND 35/50 bitumen, the composition and properties of which meet the requirements of current national regulatory documents. Results. The article presents the results of testing a method for determining the plasticity of a mastic asphalt mixture based on the immersion depth of the test rod. The advantages and disadvantages of this method and the device used to determine the plasticity of the mixture are identified, and further steps to improve it are outlined. On the basis of experimental verification of this method, its sensitivity to the composition of mastic asphalt mixtures and their production temperature was determined. It has been established that a comprehensive assessment of mastic asphalt mixtures in terms of technological and operational plasticity makes it possible to determine the optimal content of bituminous binder at the design stage of the mastic mixtures composition and to assign the most rational temperature regime for the preparation and placement of mixtures. Conclusions. On the basis of experimental verification of the method for determining the plasticity (mobility) of mastic asphalt mixtures based on the assessment of plasticity by the depth of immersion of the test device (plunger, rod, hammer) in the mixture, the possibility and expediency of its use for: designing the composition of mastic mixtures; selecting the optimal amount of bitumen and establishing acceptable technological temperatures for the preparation and placement of mixtures were established.

Ivan Balashov, Roman Sydorchuk, Viktor Skoropadskyi et al.

Introduction. New scientific achievements, modern equipment and new materials have to be used for the quality rehabilitation of the road transport network. New materials have to meet the requirements for improving the physical and mechanical properties of roads and a positive economic effect must be achieved. The role of modern and advanced material is hydro-removal ash, which not only improves the physical characteristics of mixtures and saves the funds, but also has a positive impact on the environment. This material is used as independently also in combination with other mixtures, such as: cement concrete mixture, asphalt concrete mixture, crushed stone-sand mix strengthened with mineral binders Purpose. The purpose of research is to study the effectiveness of the use of hydro-removal ash in crushed stone-sand mixtures strengthened with mineral binders, to determine the optimal volume of ash and its effect on physical parameters in different combinations with mineral binders. Materials and methods. Experimental tests of crushed stone-sand mixture 20 strengthened with mineral binder with different volume of hydro-removal ash were performed. Results. The efficiency of hydro-removal ash in crushed stone-sand mixtures strengthened with mineral binders is determined, the optimal volume of ash to reach the required physical parameters is determined, the pattern of changes in physical and mechanical parameters depending on the ash content is shown. Conclusions. Experimental tests have shown that hydro-removal ash affects effectively the physical properties of the final product, its use saves funds and natural resources, and reaches positive changes in the environment. These factors indicate that the hydro-removal ash is recommended for use in the road industry.

Aidil Abrar, Nuryasin Abdillah

Spent Bleaching Earth salah satu hasil dari limbah padat hasil proses produksi dari industri pengolahan minyak kelapa sawit. Spent Bleaching Earth (SPE) termasuk kedalam limbah hasil pemucatan industri kimia atau CPO (Crude Palm Oil), sehingga termasuk kedalam golongan bahan hasil pengolahan lemak hewan/nabati dan derivatnya. SPE merupakan bahan yang berbahaya  namun dapat di daur ulang atau di olah menjadi bahan yang bisa dimanfaatkan sebagai bahan baku dari batu bata. Dengan demikiaan timbul pemikiran untuk memanfaatkan SBE ini menjadi bahan baku untuk pembuatan batu bata. Proses pembuatan bata ramah lingkungan, limbah ini dapat digunakan dengan pencampuran semen dan pasir di aduk dengan air menjadi mortar dengan perbandingan 1 : 4. Variasi komposisi limbah SBE ini dijadikan sebagai pencampur sebagai pengganti pasir yaitu 5%, 15%, 25%, 35%,45%,55%,65% dan 95%. Dalam penelitian menggunakan metode Standar Nasional Indonesia (SNI) tentang Beton. Kuat tekan terhadap benda uji dilakukan pada umur 7 hari, dari hasil pengujian nilai yang memenuhi untuk kuat tekan dengan komposisi maksimum penggunaan SBE sebesar 15%.

Susy Srihandayani, Aidil Abrar, Surya Indrawan

Kadar air tinggi dan organik yang terkandung pada gambut sangat berpengaruh Kadar air tinggi dan organik yang terkandung pada gambut sangat berpengaruh terhadap daya dukung sebagai lapisan tanah dasar. Berbagai upaya telah dilakukan dengan perkuatan maupun modifikasi tanah secara fisik maupun kimia. Stabilisasi berbasis Ion Exchange dengan menggunakan Difa SS dan semen dapat menjadi pilihan untuk meningkatkan daya dukung tanah gambut. Penelitian ini bertujuan menganalisis pengaruh Difa SS dan semen dengan kadar tertentu terhadap tanah gambut. Dari pengujian propertis tanah, tanah gambut yang digunakan mengandung pasir dan lanau. Berbagai variasi campuran Difa SS, semen dan tanah gambut dilakukan dengan Trial and Error untuk mencapai nilai daya dukung tanah dan pengujian CBR (California Bearing Ratio) cara laboratorium dilakukan tanpa rendaman (unsoaked). Tes CBR dilakukan setelah 4 hari periode curing. Hasil penelitian menunjukkan bahwa nilai CBR dari tanah gambut kering dengan kadar air optimum 16 % dan gdmax = 0,79 gr/cm3 distabilkan menggunakan Difa SS 6% dan 4% mencapai 45,29%. Pengaruh campuran Difa SS dan semen terhadap tanah gambut yang mempunyai kadar air tinggi dapat mengurangi kadar air gambut tersebut dan meningkatkan daya dukung

Marcos Alberto Martínez Martínez, Jonathan Agüero Valverde

La sintaxis espacial estudia la configuración de elementos espaciales y las relaciones entre ellos. Para una ciudad, estos elementos son las calles que forman su red de caminos. La sintaxis espacial busca establecer relaciones entre esta composición espacial y características urbanas como el movimiento de personas y vehículos, el valor de la tierra, y la ubicación del comercio. Este estudio busca determinar la correlación entre esta configuración y el volumen vehicular que pasa por la red en la ciudad de Cartago, Costa Rica. Para obtener esta correlación, se elaboró un análisis de segmento unitario, estableciendo la prioridad de las vías en cada intersección y recopilando información al recorrer la ciudad. Posteriormente se consideran varios modelos estadísticos para encontrar el mejor ajuste de los datos. La correlación más alta se consigue al utilizar un modelo exponencial multivariado. Incluir una variable categórica para las calles con orientación Norte-Sur y flujo en una sola dirección mejora considerablemente el coeficiente de determinación; tomar en cuenta sólo una variable lleva a una sobrestimación del volumen del tráfico para estos casos. Se concluye que la sintaxis espacial es un método rápido y económico que puede brindar una guía para ejecutar estudios más detallados sobre la red actual y etapas tempranas de futuros proyectos.

Fidel García Hernández, Horacio Delgado Alamilla, Domingo Eduardo Campos Hernández

La construcción y conservación de nuevas carreteras requiere de muchos recursos tanto naturales como económicos, ya que el reciclado de materiales es una de las técnicas más utilizadas en la actualidad, por lo cual es importante conocer las propiedades mecánicas del tipo de aplicación a utilizar. El presente trabajo se enfoca en la evaluación de las propiedades mecánicas de una base estabilizada con asfalto espumado (reciclado en frio). El estudio analizó la influencia de dos variables de diseño como son el tipo de filler activo (cal y cemento portland) y el contenido de asfalto espumado (2.2 a 2.4%). Los parámetros utilizados en la evaluación fueron la resistencia a la tensión indirecta, el ángulo de fricción interna y cohesión (ensayo triaxial) y el módulo resiliente. Los resultados muestran que la inclusión de cal mejora las propiedades mecánicas de la base estabilizada. En lo referente a los parámetros mecánicos se observó que las mezclas estabilizadas con asfalto espumado presentan un aumento de su resistencia en comparación con una base granular tradicional, siendo la pérdida de cohesión el modo de falla de este tipo de estabilización

Vaidas Ramūnas, Audrius Vaitkus, Alfredas Laurinavičius et al.

As the railway lifespan is the main criterion for selection of the aggregate for ballast and for planning the maintenance of the railroad, it is important to define the relationship between the particle load resistant characteristics and a lifetime of ballast in structure. Assessment of the quality of the ballast aggregate particles under dynamic and static loading reflect both, the toughness and hardness, and these are identified with the Los Angeles Abrasion and Micro-Deval Abrasion values. The model formerly developed by Canadian Pacific Railroads was adapted to predict possible loads expressed in cumulated tonnes. Different ballast aggregate mixtures were tested in the laboratory including dolomite and granite. Calculated potential gross tonnage (expressed in Million Gross Tonnes) of the railway per lifetime for each different aggregate type presented. The outcome of this research is established classification system of railway ballast aggregate and defined Los Angeles Abrasion and Micro-Deval Abrasion values of aggregate dependently on required lifetime.

Emilia Kuliczkowska

In this paper, road pavement collapses resulting from sewer leakage are divided into six categories: negligible, marginal, considerable, serious, very serious and catastrophic, with the categorization being based on two criteria, both related to traffic safety, i.e., the number of fatalities caused by sinkholes, and the extent of the road pavement damage. The causes of road pavement collapses are also discussed. The study involved analyzing the deterioration of sewer pipes with long service lives, focusing on the most common materials, i.e., concrete and vitrified clay. The results of the sewer inspections performed by the Kielce University of Technology suggest that the spot and linear defects detected in sewers of this type can be divided into three groups. The findings were used to formulate some recommendations on how to improve road traffic safety by preventing road pavement collapses.

Mustafa Akgul, Murat Demir, Tolga Ozturk et al.

Forest road planning is a time-consuming and complicated process both because it requires environment-friendly road building, and due to the requirement to observe economic costs. This costs will be increase depending on maneuverability requirements of vehicle dimension. The main aim of this study is to analyze maneuverability of recreational vehicles on forest roads that primarily serve utilization of vehicles intended for production as well as geometrical characteristics of roads on computer environment. Both dynamic horizontal driving analysis and dynamic vertical driving analysis can be made with Autopath driving analysis module of Plateia 2013 software. Computer-aided horizontal driving analysis, which is used in examination of opportunities for utilization of available roads by different vehicle types, appears as an effective method for the decision maker in consideration of geometrical standards of vehicles during decision-making process. Graphical report is another output of driving analysis which visually presents vehicle maneuverability. In this context, Maneuverability of automobile, midibus and bus were analyzed on forest road with 4 m platform width. As a results of this study, it was concluded that computer-aided driving analysis is a beneficial tool in decision making process for re-planning of forest roads. As a consequence, it is considered that driver safety, as well as project costs, would increase by utilization of driving analysis during forest road planning and design.

Fivi Zulfianilsih, Ulfa Jusi

Salah satu permasalahan yang sering dihadapi oleh masyarakat adalah kemacetan yang berhubungan dengan volume lalu lintas di suatu ruas jalan. Penelitian ini bertujuan untuk menghitung kinerja jalan berdasarkan nilai derajat kejenuhan jalan di 4 ruas pengamatan yaitu Jalan Hang Tuah, Jalan Jendral Sudirman, Jalan Mawar, Jalan Pembangunan Kota Duri dan mencari alternatif pemecahan masalah apabila nilai derajat kejenuhan lebih dari 0,75 sesuai standar MKJI 1997. Metode yang digunakan adalah Arc View versi 3.3, Metode Roods dan Metode Arterical Capacity dengan persamaaan rumus C = Co ´ FCw ´ FCsp ´ FCsf ´ FCcs. Dari hasil perhitungan nilai kapasitas (C) maka akan didapat nilai derajat kejenuhan (DS) yang menggambarkan layak tidaknya jalan tersebut digunakan secara nyaman. Analisa yang didapat kondisi jalan yang mengalami derajat kejenuhan tinggi dengan nilai DS > 0,7 adalah Jalan Hangtuah sedangkan jalan yang mengalami derajat kejenuhan sedang dengan nilai DS antara 0,5-0,7 adalah di Jalan Jendral Sudirman, sedangkan jalan yang mengalami derajat kejenuhan rendah dengan nilai DS < 0,5 adalah di Jalan Mawar dan Jalan Pembangunan.

Arifal Hidayat

Penelitian terdahulu oleh Hidayat, A (2013) terhadap penilaian investasi BPAB Kabupaten Rokan Hulu menunjukkan bahwa Badan Pengelola Air Bersih (BPAB) kota Pasir Pengaraian Kabupaten Rokan Hulu hingga tahun 2012 hanya mampu melayani 1470 sambungan rumah atau 20,39% jumlah rumah tangga. Tujuan penelitian adalah untuk mengetahui total kebutuhan air bersih di Kecamatan Rambah  untuk 15 tahun di Kecamatan Rambah Kabupaten Rokan Hulu. Data sekunder yang digunakan yaitu  jumlah pelanggan aktif dan jumlah penduduk dengan prediksi kebutuhan air bersih pada BPAB unit Kecamatan Rambah 15 tahun yang akan datang. Metode yang gunakan dalam menghitung jumlah pertumbuhan pelanggan dan kebutuhan air bersih bersih yaitu dengan metode exponensial. Hasil perhitungan prediksi untuk 15 tahun yang akan datang jumlah pelanggan 436 pelanggan, kebutuhan air bersih = 444,049723 m3/hari. Dengan kapasitas resevoir di BPAB unit kecamatan Rambah sebesar 1.100 m3/hari, maka dengan kapasitas tersebut masih memenuhi kebutuhan air bersih di BPAB unit Kecamatan Rambah sampai dengan tahun 2028.

Linas Balčiauskas, Marius Jasiulionis

In Lithuania, one of the measures to reduce the number of wildlife-vehicle accidents (WVA) is the fencing of highways. However, any gaps in the fencing have the potential to become an animal crossing site and consequently are likely to lead to increased WVA. Attempting to reduce the number of animals venturing onto roads, trials with the chemical repellent Wam Porocol® were conducted. This was the first such investigation in Lithuania. The effectiveness of Wam Porocol® was investigated over a six-month period in five gaps in the fencing, with five parallel control places without repellent also checked. In total, 11 mammal species (nine wild and two domestic) were registered, the most frequent of which were roe deer (32 cases), red foxes (18), raccoon dogs (16), red deer and martens (14 of each), plus domestic dogs (13 cases). Hoofed animals accounted for 42.1% of the total, with wild and domestic carnivores totalling 57%. It was found that, on average, every gap in the fencing allows the passage of 300–400 mammals onto the highway annually. Applying repellent, these numbers were reduced to 170–240 animals annually. Thus, the repellent Wam Porocol® reduced the number of mammals venturing onto highways by 42%. The daily average of gap-crossing mammal numbers was significantly lower (p < 0.025) using repellent than in control places.

Carlos Eduardo Poveda Salamanca, Jaime Andrés Rojas López, Edgar Eduardo Muñoz Díaz

En este trabajo se realizó una estimación experimental de los coeficientes de fricción por desviación y curvatura de cables postensados con diferentes materiales de ductos, uno plástico y otro metálico galvanizado, por medio de su instrumentación electrónica. Para esto se construyeron dos vigas de concreto postensado, cuya instrumentación se realizó empleando un sistema de adquisición de datos y galgas de deformación, con los cuales se determinó la variación de las deformaciones unitarias y; por lo tanto, las pérdidas de tensión de los cables a lo largo de su longitud. Este diseño se concibió como un puente peatonal tipo viga losa. Conociendo la geometría y las fuerzas de tensionamiento en cada punto de los cables, se estimaron los rangos de los coeficientes de fricción por desviación no intencional (k) y curvatura (μ), los cuales se compararon con las normas nacionales e internacionales. En esta investigación, se obtuvo para los ductos metálicos, que los rangos de sus coeficientes de fricción por desviación no intencional (k) son similares a los recomendados por las normas, mientras que los coeficientes por curvatura (μ) son mayores. Para los ductos plásticos, los valores de sus coeficientes de fricción (k y μ), estimados en esta investigación son innovadores, ya que las normas consultadas no los especifican, por lo cual se constituyen en un aporte para la ingeniería nacional. Dicho trabajo es una base o semilla, que puede ampliarse con más investigaciones y posteriormente servir para las actualizaciones de la norma nacional. Este trabajo se realizó gracias al apoyo de VSL INTERNACIONAL y CEMEX, generando transferencia en tecnología e innovación para la industria y la sociedad.

Lina Bertulienė

This summary of the author’s PhD thesis supervised by Prof Dr Alfredas Laurinavičius and defended on 21 December 2011 at the Vilnius Gediminas Technical University. The thesis is written in Lithuanian and is available from the author upon request. Chapter 1 covers the analysis of the literatute. There is the review of research works carried out in Europe and other countries of the world for determining structural strength of road pavements by calculation methods during their design and gives a wide description of the main methods used in Lithuania. Chapter 2 gives the analysis of the effect of different factors on the road pavement strength, studies a damaging impact of the axle loads of moving vehicles on road pavement, also the dependency of strength and condition of road pavement on the changes in the ambient temperature and seasonal precipitation. Chapter 3 analyses the stages of experimental research, selection of a test section for experimental research, methodology for investigating pavement structure parameters and the equipment used, gives the analysis of research data obtained by the author. Chapter 4 describes statistical analysis and assessment of research results obtained on the subgrade and the lower pavement layers. Reduction coefficients are suggested to be used betwen the static and dynamic measuring methods.

Audrius Vaitkus, Daiva Žilionienė, Sabina Paulauskaitė et al.

The bonding of asphalt layers has direct reliance on road pavement structures strength and durability. Because of insufficient bond between pavement layers the slippage and corrugations, rutting and cracking occur and the pavement life cycle becomes shorter. The article describes the research on bonding of asphalt layers, which was carried out in 2010–2011 at Vilnius Gediminas Technical University Road Research Institute. In this research the strength of layers bonding was assessed using the direct shear (Leutner) test without normal stress in the specimen. The samples were taken from the road sections of Lithuania with standard asphalt layers, also asphalt layers with the geosynthetic interlayer. The research showed that the bonding strength of asphalt layers of the samples taken on the roads of Lithuania in most cases meets the requirements of standard documents, and the use of geosynthetic materials between asphalt layers worsens their bonding strength.

Sanja Dimter, Tatjana Rukavina, Ivana Barišić

Application of nondestructive methods in assessing the properties of materials and mixes is very popular because of their simplicity and noninvasive nature. The ultrasonic method is, as one of nondestructive methods, used for more than 60 years in determining the properties of concrete mixes. However, only recently it has been applied application in studies of the stabilization mixes intended for road construction. The ultrasonic method is based on measurement of the travel time of longitudinal ultrasonic waves through the sample. In this paper, the investigation of stabilized mixes containing sand from river Drava stabilized with cement and fly ash are presented. The aim of the research was to determine the impact of changes in the composition of mixes and in the regime of care on the density, compressive strength and ultrasonic velocity. An additional goal was to analyze the relationship between the investigated properties of mixes and the ultrasonic velocity. The compressive strength of the stabilized mixture is determined by the destructive method according to Croatian Standards HRN.U.B1.030 Unconfined Compressive Strength as the average stress in a sample during uniaxial compression testing at the ultimate force. Testing of density and compressive strength of mixes and determination of the ultrasonic speed has been performed after 7, 28 and 90 days of curing at four different temperatures: 5 °C, 15 °C, 25 °C and 35 °C. The obtained results indicated the direct influence of fly ash quantity on the observed properties. Increase in the amount of fly ash caused a decrease in the mixture compressive strength, its density and ultrasonic velocity. A significant influence of treatment temperature on the compressive strength, density and ultrasonic velocity was also observed. Finally, correlation between density and ultrasonic velocity, as well as compressive strength and ultrasonic velocity was established. Exponential relationship between the compressive strength of stabilized mixes and ultrasonic velocity proved to be very strong, and similar to those obtained in previous studies by other researchers. Test results showed that the ultrasonic method can be useful in assessing properties of stabilized mixes.