Papers by Keyword: Triaxial

Abstract: The strength of a fine-grained lateritic soil from three (3) different locations on Abuja – Lokoja road where road failure occur was treated with sodium silicate activator (SSA), cement and rice husk ash (RSA) with varying percentage scrutinized by means of Atterberg, compaction and triaxial shear tests. The result reveals that cement additive improved the lateritic soil from Liquid limit values of 41.25 at 0% to 44.36 at 8%, but reduces at 10% to 35.67, while RHA increases at increased percentages. The MDD improved with increase in the quantities of all the additive (SSA, cement and RHA) content, while OMC for both cement and RHA reduces from 18.65% at 0% to 11.71 and 18.05 respectively. It reveals cohesion of the soil at 0, 2, 4, 6, 8 and 10% to be 19, 39, 49, 55, 58 and 65 KN/m² respectively, with highest angle of 65⁰ and lowest of 37⁰. This implies that the cohesion of the improved sample was satisfied since the improved angle of internal friction is above the angle that makes soil very plastic which is 28⁰. Keywords: Geopolymer. Sodium silicate, rice hush ash, Triaxial, Abuja.

Abstract: An unconsolidated undrained (UU) test is one type of triaxial compression tests based on the nature of loading and drainage conditions. In order to imitate the UU triaxial compression tests, a UU triaxial emulator with a graphical user interface (GUI) was developed. It has 5 deformation sensors (4 radial deformations and one vertical deformation) and one axial pressure sensor. In addition, other inputs of the emulator are the cell pressure, the height of sample, and the diameter of sample, which are provided by the user. The emulator also facilitates the analysis and storage of measurement data. Deformation data fed to the emulator were obtained from real measurements [H. Nawir, Viscous effects on yielding characteristics of sand in triaxial compression, Dissertation, Civil Eng. Dept., The University of Tokyo, 2002]. Using the measurement data, the stress vs radial strain, stress vs vertical strain, and Mohr-Coulomb circle curves were obtained and displayed by the emulator.

Abstract: Replacement rate is an important factor that affects the mechanical properties of recycled concrete. In order to study the influence of replacement rate on triaxial mechanical performance of recycled concrete, 20 recycled concrete cylinder specimens for conventional triaxial loading test with recycled aggregate replacement rate as changing parameters were designed. The results show that replacement rate has a great influence on peak stress of recycled concrete specimens under uniaxial stress, but the effects of replacement rate gradually decreased with the increase of lateral confining pressure. The influence of replacement rate on peak strain is larger than peak stress, the impact of replacement rate on peak strain gradually decreased with the increase of lateral confining pressure. The elastic modulus of recycled concrete specimens changes with different replacement rate, and the fluctuations is in the range of 20%. The results will provide reference for further theoretical study of recycled concrete.

Abstract: It is well established that lateral confinement of concrete enhances its axial strength and deformability. It is often assumed that, at a same level of confining pressure, the axial compressive stress and strain of fiber reinforced polymer (FRP)-confined concrete at a given lateral strain are the same as those in concrete actively confined concrete. To assess the validity of this assumption, an experimental program relating both types of confinement systems was conducted. 25 FRP-confined and actively confined high-strength concrete (HSC) specimens cast from a same batch of concrete were tested under axial compression. The axial stress-strain and lateral strain-axial strain curves obtained from the two different confinement systems were assessed. The results indicate that, at a given axial strain, lateral strains of actively confined and FRP-confined concretes correspond, when they are subjected to the same lateral confining pressure. However, it is observed that, at these points of intersections on axial strain-lateral strain curves, FRP-confined concrete exhibits a lower axial stress than the actively confined concrete, indicating that the aforementioned assumption is not accurate. The test results indicate that the difference in the axial stresses of FRP-confined and actively confined HSC becomes more significant with an increase in the level of confining pressure.

Abstract: A numerical triaxial apparatus based on discrete element method is developed on the platform of Yade using Python script. A DEM model with rolling resistance contact considered is proposed for dense granular materials, which is then applied in triaxial compression test of Chende sand. Stress-strain response and volume-axial strain response of the DEM model agree well with that of experiments, with a good prediction of dilatancy angle. Degradation of granular materials duo to particle erosion is also investigated using triaxial compression tests. It is indicated that peak friction angle decreases with the remove of particles if strong force network of granular materials is destroyed.

Abstract: This paper introduced a measuring soil sample triaxial volume displacement system that used position sensing detector.The system course of principle and development was maken a detailed statement. The study was carried through literature [12] existing shortcomings. The shortcomings of former system was mended in the new system .This system had a high measuring precision and reasonable design. This systems triumphantly developed will be applied in triaxial specimens local sheared and port restriction .This system have greatly applied foreground to study deformation localizing , come into being cut strip and measuring volume change of unsaturated soil.

Abstract: This study examines the effect of particle size on the behaviors of triaxial sand specimens. In order to investigate the material behaviors (i.e., local void ratios and inter-particle contacts) as well as the mechanical behaviors, three numerical triaxial tests assigned with different particle size ranges were performed. The results showed that the specimen with uniform particle sizes exhibited higher strength, larger local void ratios and more inter-particle contacts than the specimen of wider size ranges.