Papers by Keyword: Ion Concentrations

Abstract: In this paper, a device for pore solution extraction from cement-based materials was presented, The relevant Factors of Efficiency of Pore Solution Extraction and the effects of squeezing pressures on the chemical concentrations of pore solutions were studied. The results shows, the efficiency of pore solution extraction can be effected by pressure values, squeezing duration, pressure maintaining time; A low rate of pressures loading is suitable for early-age cement pastes, and long-term samples can take larger rate; 30 minutes loading time can be adopted for specimens with all the different ages; no significant differences were observed regarding the chemical composition (Na and K) of the pore solution extracted between 300 and 900MPa.

Abstract: The spatial-temporal variability of karst water chemistry is affected by lithological information, precipitation and agricultural activities. Based on the data of 10 hydro-chemical monitoring stations in Houzhai karst basin from 1989 to 2001, the spatial-temporal variability of karst water chemistry and the relationships between karst water chemistry dynamic and their main control factors were interpreted and analyzed by using the integrating methods of the stochastic theory and geostatistics. The results indicate that the karst water chemistry dynamic of Houzhai karst basin show obvious spatial-temporal distribution characteristics. The temporal variations of main ions are closely related to precipitation. The main ions vary regularly in space because of lithological and karst morphology, but the spatial variations of K⁺, Na⁺ are controlled by agricultural activities.