The Effects of Different Nanoadditives on the Physical and Mechanical Properties of Similar Silty Mudstone Materials

Abstract

In order to analyze the influence of different nanoadditives on the physical and mechanical properties of similar silty mudstone materials, nano-TiO2 (NTi), nano Al2O3 (NAl), and nanobentonite (NBe) were added to improve the physical and mechanical properties of silty mudstone similar materials. The physical and mechanical parameters are more in line with silty rock. Finally, nanometer additives suitable for silty mudstone similar materials are determined by conducting density test, natural water absorption test, uniaxial compression test, splitting test, softening coefficient test, expansibility test, and microscopic test. The effects of adding NTi, NAl, and NBe on improving the physical and mechanical properties of silty mudstone similar materials were studied to analyze the influence law of different NTi, NAl, and NBe contents on similar material density, natural water absorption, uniaxial compressive strength, tensile strength, softening coefficient, expansion rate, and other physical and mechanical parameters. The microscopic morphology of similar materials was analyzed by scanning electron microscopy and the mechanism of influence of nanoadditives on the microscopic structure of samples was revealed. The results are as follows. (1) The density of similar materials of silty mudstone increases with the increase of the content of nanoadditive. The natural water absorption rate decreased first and then increased with the increase of the content of nanometer additives, while the softening coefficient decreased with the increase of the content of nanometer additives. The uniaxial compressive strength and tensile strength increased first and then decreased with the increase of the content of nanometer additives. This is due to the incorporation of the nanoadditive amount effective to promote the hydration reaction of gypsum and accelerate the production of cement, while a similar material may be filled in the pores, reducing the internal defects, a similar material to make denser; when excessive dosage, nanoadditives agglomeration occurs, resulting in deterioration of the effect, but will reduce the mechanical properties of similar materials. (2) When the content of NBe is 6%, the physical and mechanical parameters of similar materials can reach or be closer to the silty raw rock except uniaxial compressive strength. The failure mode of the uniaxial compression specimen is also the same as that of the original rock, which can be used as the best choice. The research results laid the foundation for further analysis of NBe application in similar materials.

Study on the Strength and Failure Characteristics of Silty Mudstone Using Different Unloading Paths

“…To mitigate the impact of initial states on results, similar material specimens exhibiting excellent homogeneity were prepared. Silt-like specimens, composed of Nano-TiO 2 , Nano-Al 2 O 3 , NTi, Nano-bentonite, gypsum, and barite powder mixed with water, bore a close resemblance to silty mudstone in terms of its physical and mechanical characteristics, as reported in previous studies [25][26][27]. The silt-like mudstone specimens were tested using a controlled moisture content of 17.5%, which is within the range found in original rock (14.6-21.5%).…”

Mixing Ratios and Cementing Mechanism of Similar Silty Mudstone Materials for Model Tests

“…en, the similarity ratios of other properties can be obtained, as shown in Table 1. erefore, the target properties of similar materials are derived from the properties of the raw rock based on the similarity ratios [13,14].…”

“…Because the content of every component has a dominant influence on the physical and mechanic properties of similar materials [13], the water content, barite powder ratio, gypsum mass, and clay mineral ratio were chosen as factors in the orthogonal test design. e barite powder ratio is the ratio of the mass of barite powder to the total mass of gypsum and barite powder, and the clay mineral ratio is the mass ratio of clay minerals to all solid components.…”

“…Similar materials can also be adopted to prepare physical models for similarity model tests, so the connection between models and prototypes can be identified [10,11]. Finally, the engineering performance of the prototype can be predicted according to the similarity criterion [12,13].…”

Research on Arch Model and Numerical Simulation of Critical Water and Sand Inrush in Coal Mine near Unconsolidated Layers

“…Some scholars have also conducted in-depth research on similar simulated materials. Through different ratios of similar materials, simulated materials with similar physical properties of rock formations are obtained, and the internal mechanism of thick loose seams in the process of coal mining is analyzed through internal physical experiments, the law of sinking [29][30][31][32].…”