Exploitation
Sina Ghavami; Ebrahim Ghasemi; Mohammad Hossein Kadkhodaei; Ali Farhadian
Abstract
Consumption of cutting and polishing tools is a critical economical parameter during quarrying and processing of granitic building stones, which is highly affected by stone abrasivity. So, estimation of abrasivity for these stones is a very important issue. There are several methods to determine the ...
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Consumption of cutting and polishing tools is a critical economical parameter during quarrying and processing of granitic building stones, which is highly affected by stone abrasivity. So, estimation of abrasivity for these stones is a very important issue. There are several methods to determine the stone abrasivity. One of the most commonly used methods is Cerchar abrasivity index (CAI). This study mainly focuses on investigating the relationship between CAI with petrographic and physico-mechanical properties of granitic building stones. For this purpose, 14 different types of commercial granitic building stones, collected from different regions of Iran, were subjected to laboratory investigations and the effect of the petrographic and physico-mechanical properties of these stones on CAI was examined using simple and multiple regression analysis. Meaningful and reasonable relationships were observed. According to the obtained results, equivalent quartz content (EQC) of granitic building stones was found to be the most effective parameter on CAI. Using linear and nonlinear regression analysis, two empirical correlations for CAI prediction based on EQC were developed. The results showed that both linear and nonlinear correlations have high performance with determination coefficients (R2) of 0.876 and 0.882, respectively. These correlations can determine the CAI with acceptable error, with root mean square error (RMSE) and mean absolute error (MAE) values of 0.135 and 0.105, respectively. Furthermore, the relationship between the diamond segment wear (SW) and CAI was investigated for the studied stones. The results showed that SW is directly related to the CAI, and there is a strong linear correlation between these two parameters with R2 of 0.787. The proposed correlation can be applied for fast prediction of cutting tool wear for practical applications in building stone processing plants with circular sawing machine, which can lead to enhanced cutting efficiency and productivity.
Mehdi Hosseini; Alireza Dolatshahi; Esmaeel Ramezani
Abstract
This work investigates the effect of adding micro-silica as a pozzolan and a replacement for part of concrete cement when placing concrete in an acidic environment. Two types of ordinary concrete and concrete-containing micro-silica are constructed. The specimens are subjected to 0, 1, 5, and 10 cycles ...
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This work investigates the effect of adding micro-silica as a pozzolan and a replacement for part of concrete cement when placing concrete in an acidic environment. Two types of ordinary concrete and concrete-containing micro-silica are constructed. The specimens are subjected to 0, 1, 5, and 10 cycles for two hours inside two types of acidic water containing sulfuric and nitric acid with pH = 3 and normal water with pH = 7. Mechanical properties including Brazilian tensile strength and uniaxial compressive strength, and physical properties including effective porosity, water absorption, and the longitudinal wave velocity of specimens are determined after the mentioned number of cycles. Thr results show that by decreasing the pH and increasing the number of cycles, the effective porosity and water absorption increase, and the velocity of longitudinal waves, Brazilian tensile strength, and uniaxial compressive strength of concrete decrease. Replacing 10% of micro-silica as a part of concrete cement has boosted the durability of concrete in corrosive conditions containing sulfuric and nitric acid more than ordinary concrete.
