Each WC particle was compressed from all sides by the neighboring WC and Co particles, resulting in quasi-isostatic compression. Those papers found that the deformation and fracture of single crystals under high isostatic pressures were accompanied by a sharp increase in the dislocation density. The results were analyzed using experimental data published previously on the effect of high isostatic pressure on the multiplication of dislocations and the fracture of single crystals. Scanning electron microscopy photographs of the indenter imprints showed massive cracking of the WC grains. Hardness measurements at different loads up to 300 N showed that hardness increased at CIP pressures up to 0.3 GPa and slightly decreased in CIP at 0.4 GPa. An intermetallic Co.sub.0.8W.sub.0.2 phase emerged in the samples subjected to preliminary CIP at 0.4 GPa. The Co layer became thinner with pressure being increased to 0.3 GPa and slightly thicker at a pressure of 0.4 GPa. The WC grains refined when CIP pressure increased to 0.2 GPa but slightly coarsened after CIP at 0.3 and 0.4 GPa. The coercive force increased nonmonotonically with pressure. The density of the CIP samples increased linearly with pressure prior to sintering and reached its maximum at 0.2 GPa for the sintered CIP samples. Transformer oil served as the pressure transmission medium. A multiplication installation was employed for cold isostatic pressing. Results revealed that the texture coefficient is a useful parameter for predicting geotechnical properties of the rocks.Abstract : The paper examines how cold isostatic pressing (CIP) of powder samples preformed by uniaxial pressing at up to 0.4 GPa influenced the density, coercive force, structure, hardness, and phase composition of the WC-8 wt.% Co (VK8) hardmetal after sintering in vacuum. Based on the results, the trend lines of E, H S, UCS, I S(50) and BPS models are more fit to yвЂ‰= x line and shows high validity of experimental models. Experimental and calculated values of geotechnical properties that obtained from laboratory tests and predicted by statistical models were compared with 45В° line ( yвЂ‰= x). Performance appraisal shows the model of BPS and TC has a higher performance than the other models. Statistical coefficients including R, RMSE, VAF, MAPE and PI were calculated to assess performance and validity degrees of obtained equations and the regression analyses. Also, no good relations were found between TC and n, W a and V P. The regression analyses indicated good correlations between TC and engineering properties, especially between Оі dry, Оі sat, H S, UCS, I S(50) and BPS. Good direct linear relationships were found between TC and percent of calcite and quartz with high correlation coefficient ( RвЂ‰=вЂ‰0.79 and 0.85). Three variable map shows that TC of the studied rocks is controlled by the presence of major minerals including quartz and calcite. Regression coefficient ( R) was obtained between вЂњ0.10 and 0.98вЂќ by simple regression analysis. Texture coefficient and required parameters were determined by JMicroVision (v1.27) software. Petrographic, mineralogical and textural investigations were studied by thin section and X-ray diffraction methods. Physical, index and mechanical properties namely specific gravity, dry and saturated unit weights, porosity, water absorption, slake-durability index, Schmidt rebound hardness, P-wave velocity, uniaxial compressive strength, point load strength index, Brazilian tensile strength and block punch strength were determined in the laboratory. For this purpose, nine rock block samples were collected from quarries and road trenches in northern and northwestern parts of Damghan, northern Iran. The effect of petrographic and textural characteristics on geotechnical properties of some carbonate rock samples including limestone and travertine was investigated using Texture Coefficient (TC) and regression analyses.

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