In any underground facilities especially tunnels, it is essential to seal the area against water ingress and leakage of reserved materials. Grouting is a common method used to seal rocks around tunnels, successful grouting reduces the duration and cost of the construction, guarantees better working environment and higher safety, minimizes the maintenance and most important decreases the corresponding environmental hazards significantly. Achieving a sufficient grout spread is one of the prerequisites for a successful and efficient sealing, the penetration of a grout is defined as the length of how far grout penetrates in the rock through fractures from a bore hole. Chemical grouts and cement-based grouts are the prevailing ones among the grouting materials. Despite the better penetrability of chemical grouts, they are unfavorable to use due to environmental hazards associated to them, whilst cement-based grouts are more convenient to use because of their low cost and low environmental impact.The major drawback with cement-based grouts is their limited ability to penetrate the very narrow fractures which is directly related to their filtration tendency which is defined as the tendency of cement grains to agglomerate and build an impermeable filter cake during the flow. Many previous studies investigated the factors that affect the filtration tendency. They drew different conclusions and suggested various methods to improve the penetrability of cement-based grouts.The mixing method is one of the factors that have a great influence on the penetrability of the grout. An effective mixing method improves the dispersion of cement particles in the mixture, thus the penetrability of the grout. As it is known from previous studies, the finer the cement particles the harder to disperse. Grouts based on micro-fine cement (< 30 μm) are essential for the development of grouts that can seal very narrow fractures (20-50) μm compared to (70-80) μm at the present.In this study, the dispersion efficiency of three different mixing methods was evaluated, a conventional lab dissolver equipped with 90-mm disk, a conventional lab dissolver equipped with R/S system and an ultrasound UP400St device. Two cement types, INJ30 and UF12, that are similar in chemical composition but differ in degree of milling were tested. Dispersion was tested with filter pump.The results showed that the conventional lab dissolver equipped with 90-mm disk is ineffective method. The conventional lab dissolver equipped with R/S system is a better method compared to the 90-mm disk but still not effective enough especially when it comes to grouts based on ultra-fine cement (UF12). The ultrasound dispersion is not only the best method between the three methods in comparison, but even more stable and reliable. The best result obtained was grout based on UF12 passing through the 54 μm filter. This could mean that fracture aperture down to 55 μm now can be sealed. This is a significant improvement but there is still a marginal for further improvements. In combination with the dispersion efficiency of different dispersion methods, the study investigated the effect of additives on dispersion in particular and penetrability in general. Results showed that additives do not directly contribute to better dispersion, but they are necessary for better spread since they affect the flow properties.

The rheological properties of cement based grouts change with water/cement ratio and time, during the course of hydration. For this reason, it is desirable to be able to measure this change continuously, in-line, with a robust instrument during the entire grouting operation in the field. The rheological properties of commonly used cement grouts were determined using the Ultrasound Velocity Profiling combined with the Pressure Difference (UVP+PD) method. A non-model approach was used that directly provides the properties, and the results were compared with the properties obtained using the Bingham and Herschel-Bulkley rheological models. The results show that it is possible to determine the rheological properties, as well as variations with concentration and time, with this method. The UVP+PD method has been found to be an effective measuring device for velocity profile visualization, volumetric flow determination and the characteristics of the grout pump used. / <p>QS 2013</p>

Grouting is performed in order to decrease the permeability and increase the stiffness of the material, especially soil and rock. For tunnelling and underground constructions, permeation grouting is done where cement based materials are pumped inside drilled boreholes under a constant pressure, higher than the ground water pressure. The aim of permeation grouting is to reduce the water flow into tunnels and caverns and to limit the lowering of the surrounding groundwater table. Cement based materials are commonly used as grout due to their availability and lower costs. To obtain a proper water sealing and reduce the lowering of the ground water table, a desired spread of grout must be achieved and the rheology of the cement grout is the governing factor for estimating the required spread. Rheological properties of cement grout such as viscosity and yield stress are commonly measured off-line using laboratory instruments, and some simple tools are available to make field measurements. Although the rheological properties of the grout that is used play a fundamental role in design and execution, no method has yet been developed to measure these properties in-line in field work. In addition to the real time measurement, there is no standard method for determining the yield stress for grouting applications. Despite the common usage of Bingham model fitting to determine the yield stress, the range of shear rate is often not specified or is neglected.   In this work, an in-line rheometry method combining the Ultrasound Velocity Profiling (UVP) technique with Pressure Difference (PD) measurements, known as “UVP+PD”, was successfully tested for continuous in-line measurements of concentrated micro cement based grouts. A major obstacle of using the ultrasound based methodology was the transducers, which would be capable of emitting sufficient acoustic energy and can be used in field conditions. The transducer technology was developed in a parallel project and the Flow-Viz industrial rheometer was found to be capable of detail measurement of the velocity profiles of cement grout. The shape of the velocity profiles was visualized, and the change in the shape of the profiles with concentration and time was observed. The viscosity and yield stress of the grout were determined using rheological models, e.g. Bingham and Herschel-Bulkley. In addition, rheological properties were determined using the non-model approach (gradient method) and the tube viscometry concept and were compared with results obtained using the rheological models. The UVP+PD method was found to be capable of determining the rheological behavior of cement grout regardless of the rheological model. The yield stress of cement grout was investigated using off-line rheometry techniques and UVP+PD in-line measurements. Tests were performed applying different shear histories and it was found that two ranges of yield stress indeed exist. Therefore, the design value of yield stress should be chosen with respect to the prevailing shear rate at the grout front for the required spread of grout. In addition, an appropriate shear rate range should be used when a Bingham fitting is done to determine the yield stress. In order to estimate the shear rate, plug thickness and velocity for one dimensional and two dimensional geometry, a non- dimensional nomogram was developed. The advantage of using the nomogram is that it does not depend on the applied pressure and the rheological properties of the grout and can therefore, be used as a simple design tool. Analytical approaches were used for the estimation and good agreements were found with numerical calculations and experimental results. In conclusion, in this work, it was found that it is possible to continuously measure the velocity profiles and determine the change of the rheological properties of cement grout using the ultrasound based UVP+PD method under field conditions. The yield stress was also investigated and it was found that two range of yield stress exist depending on the prevailing shear rate of the grout, which should be used for designing the grouting time at different conditions. In order to decide the design value of yield stress for grouting applications, a non-dimensional nomogram was developed that can be used to estimate the plug thickness, shear rate and velocity of the grout. / <p>Funding for the project was provided by the Swedish Rock Engineering Research Foundation (BeFo), The Swedish Research Council (FORMAS) and The Development Fund of the Swedish Construction Industry (SBUF), who are gratefully acknowledged. QC 20151112</p>

The thesis is aimed at deepening knowledge about the design and use of open-graded asphalt concrete filled with a special cement grout. The first part is the issue discussed theoretically with reference to the real possibility of practical application, a description of the various manufacturers and their patented technologies. The second part of this work is devoted to assess the resistance of this technology to chemical de-icing agents.

Aim of this thesis is the usage of the open-graded asphalt concrete filled with a special cement grout in the road structures. Thesis defines the main concrete properties and explains related legislation and norms that apply. In addition, laboratory design of asfalt mixtures and a tree kind mortal filler and possibilities of mortal filler pigmentation are dealth with. Finally, thesis evaluates the results from various laboratory tests that were performed on the specimens made from final mixtures.