Bitumen plays a significant role in our daily lives, primarily used in road construction. The main source of bitumen is oil refineries, and bitumen from Qayyarah is considered an important resource in Mosul. The oil from Qayyarah is a heavy crude with an aromatic origin, and the high-productivity bitumen can be extracted from it, reaching up to 48% and more than a thousand tons daily. However, it fails the Indirect Tensile strength tests of the asphalt mixtures used in road paving. We attempted to improve its engineering properties, particularly by increasing the Indirect Tensile strength, using three treatment methods for Qayyarah bitumen, so it remains competitive in the Iraqi market by utilizing cheap and readily available materials like elemental sulfur, low-density polyethylene waste, and C9 petroleum resin, each mixed in two different ratios for processing to reduce industrial operation costs. Our goal was to help Qayyarah bitumen succeed in the engineering mixtures, with the added ratios being 1% and 2% for elemental sulfur, low-density polyethylene, and petroleum resin C9. The results were excellent, showing a clear improvement in the Indirect Tensile strength test of the asphalt mixtures, an increase in their load-bearing capacity (Marshall test), and homogeneity in Scanning Electron Microscope (SEM) images. The prepared samples did not suffer from phase separation and were within the allowable range.

The Tensile strength (σ t) of a rock plays an important role in the reliable construction of several civil structures such as dam foundations and types of tunnels and excavations. Determination of σ t in the laboratory can be expensive, difficult, and time-consuming for certain projects. Due to the difficulties associated with the experimental procedure, it is usually preferred that the σ t is evaluated in an Indirect way. For these reasons, in this work, the adaptive network-based fuzzy inference system (ANFIS) is used to build a prediction model for the Indirect prediction of σ t of sandstone rock samples from their physical properties. Two ANFIS models are implemented, i. e. ANFIS-subtractive clustering method (SCM) and ANFIS-fuzzy c-means clustering method (FCM). The ANFIS models are applied to the data available in the open source literature. In these models, the porosity, specific gravity, dry unit weight, and saturated unit weight are utilized as the input parameters, while the measured σ t is the output parameter. The performance of the proposed predictive models is examined according to two performance indices, i. e. mean square error (MSE) and coefficient of determination (R2). The results obtained from this work indicate that ANFIS-SCM is a reliable method to predict σ t with a high degree of accuracy.

The Tensile strength of rocks plays a noteworthy role in their failure mechanism, and its determination can be beneficial in optimizing the design of the rock structures. Schistose rocks due to their inherent anisotropy in different foliation directions show a diverse strength at each direction. The purpose of this work was to compare and assess the Tensile strength of phyllite, which was obtained in direct and Indirect Tensile tests in different foliation directions. To this end, several phyllite specimens with different foliation angles (0º , 30º , 45º , 60º , and 90º ) related to the loading axis (β ) were prepared. Finally, the direct Tensile test, diametrical and axial point load tests, Brazilian test, and Schmidt hammer test were conducted on 188 samples. The results of the experimental tests revealed that the maximum and minimum Tensile strengths in direct Tensile testing tension were directly related to the angles of 0º and 90º . Also it was observed that the Brazilian Tensile strength overestimated the Tensile strength. Furthermore, an exponential correlation was introduced between the direct Tensile strength and the Brazilian Tensile strength.

Dealing with problematic soils is one of the most challenging parts of geotechnical engineers’ careers. Loose sand is one of them due to its low cohesion and can be found worldwide, specifically in coastal regions. Chemical stabilizers like cement are of the prevalent ones among engineers to deal with the weaknesses of loose sand. However, the substitution of these traditional stabilizers with pozzolanic materials like natural zeolite become approved since it helps reduce cement consumption and hence, lower CO2 emission. Despite all advantages, brittle behavior is an unwelcome consequence of these stabilizers. Therefore, the aim of this study is to reduce the brittleness of the cement-zeolite-stabilized sand employing natural kenaf fibers. To this end, two cement contents, four amounts of zeolite replacement of cement, and three fiber contents in three lengths were adapted in two relative compactions (RC) to investigate the compaction, 8-shape direct Tensile strength (DTS), and Indirect Tensile strength (ITS) behaviors. Experimental efforts revealed that compaction behavior is sensitive to stabilizer contents and fiber content and length. The addition of the 8% cement, increase of the zeolite up to 50%, and fiber increment up to 1.5% led to the reduction of the compaction properties; however, optimum moisture content increased with the rise in kenaf fiber. A notable influence on the DTS and ITS behavior was observed while 30% zeolite replacement in 8%-cemented samples and reinforced with 1% kenaf fiber with 10mm length. Furthermore, a linear relationship was presented between DTS and ITS. In the end, the reinforced sample was analyzed using Scanning Electron Microscope (SEM) images.

Acoustic emission is a high-frequency elastic signal that is generated and emitted by a material when it is loaded. Transient elastic waves are created by the release of energy in the sources in the material. Acoustic emission test is one of the methods of non-destructive tests. These waves are emitted in the material and can be received by acoustic emission sensors. Acoustic emission method can monitor the solids’ fracturing process during a period of time, and this method is extensively used in studying the fracturing process and inspections. In the present study, Tensile splitting and uniaxial compressive tests were done on concrete sample accompanied by AE (acoustic emission) monitoring. The chart of AE parameters were analyzed; the parameters include energy, energy cumulative values as well as amplitude values, duration, average frequency, rise angle, b-value, and improved b-value relative to the stress applied to the specimens during the loading time. Based on the results, most of the crack growth signals in Tensile splitting tests were Tensile crack signals, and there are fewer shear crack signals; however, in uniaxial compressive tests, there were more shear cracks. Moreover, the b(Ib)-values can be used for predicting damages in large scales during the fracturing process in specimens, based on AE parameters.