Effect of Hydrochloric Acid on Different Ratios of Cement-sand Mortar

Testing Hydrochloric Acid on Cement-sand Mortar

Abstract

Quality evaluation and quality assurance are the most important parameters which ensure the quality of any building material. For this reason, building materials are always analyzed by using different international test methods for checking and confirming their quality provided in the standard specifications. For this, first raw materials are examined (physically and chemically) and their results are compared with the international standard specifications to confirm their suitability. Cement-sand mortar cubes of different proportions are prepared and cured for 28 d. The physical suitability of mortar is ensured by calculating compressive strengths, while cement sand proportions are re-confirmed by adopting the test method BS 4550: 1970. The samples of known proportion were treated with the different concentrations of hydrochloric acid (HCl) which vary from 5 M to 11 M and each molar solution was further classified as 1:7 and 1:9 and 1:11 dilution with water. Dilution of the HCl solution has proved to be ineffective in the proper decomposition of hydrates of cement. Cement contents do not dissolve in the solution completely and deviation in results is observed. The reactivity order of HCl solution with respect to its ratios is  1:7>1:9

>1:11 for all molarities. Great variations in the results from 5 M (1:11) to 11 M (1:7) have been observed when graphs are plotted between mix ratio results and molarities. Linearity in a graph is achieved with a high concentration of HCl i-e 11 M (1:9), the solution gives the most accurate result. Accuracy in the results of mortar samples cannot be achieved utilizing different diluted HCl solutions. It is concluded from the data that by diluting HCl solution, test results drastically changed from standard values.