Swelling behaviour of soil–bentonite mixtures

Abstract

Studies on the swelling behaviour of mixtures of bentonite clay and nonswelling coarser fractions of different sizes and shapes reveal that observed swelling occurs only after the voids of the nonswelling particles are filled up with swollen clay particles. The magnitude of the swell within the voids, called intervoid swelling is large when the size and percentage of the nonswelling coarser fraction is large. The observable swell, after intervoid swelling, is called primary swelling and follows a rectangular hyperbolic realtionship with time. The total swell per gram of the clay decreases with an increase in the size of the nonswelling fraction and with a decrease in the percentage of swelling clay. Time–swell realionships show that swelling continues to occur for a long time after the primary swelling, and this is called secondary swelling. Key words: clay, expansive soil, swelling, time factor.

Influence of Particle Morphology on the Hydraulic Behavior of Coal Ash and Sand

“…Concerning composite materials, it also has been studied the use of bentonite addition in soils with hydraulic conductivity values unacceptable (more than 10 -9 m/s) to be used as liner materials (Graham et al 1989;Kozicki et al 1994;Umedera et al 1996;Sivapullaiah et al 1996). According to these authors, bentonite addition up to a threshold value of 14% would be enough to reduce the hydraulic conductivity to acceptable values (Yan Ree et al 1992;Kozicki et al 1994;Umedera et al 1996;Alston et al 1997).…”

Study on the swelling behaviour of blended clay–sand soils

“…For mixes with 10% and 20% clay, the clay particles were contained in the sand matrix (e si < 0.9) such that swelling in the clay phase was not sufficient to disrupt granular contact. Therefore, most of the volume increase took place during the initial swelling stage and a distinct primary stage was not observed (Sivapullaiah et al 1996). Further, the entire SP was generated within 10 min of water addition to the samples as indicated by the asymptotic portion of the SP versus time curves.…”

“…Developed during the geological cycle of depositionburial-uplift-erosion (Bell 1993), the inherent compositional characteristics of natural soils give the range of volume increase. Mineralogy (Azam 2003), ion exchange (Mitchell and Soga 2005), particle characteristics (Sivapullaiah et al 1996), and pore water chemistry (Simons and Reuter 1984) are collectively manifested in soil consistency that can be empirically correlated with soil swelling. The actual value of increase in volume is determined by environmental factors which, in the time frame of engineering importance, are related to human and climatic activity (Abduljauwad et al 1998).…”

Morphological and strength analysis of PCC bottom ash amended with bentonite

“…Therefore, some researchers have studied the possibility of use of PCC bottom ash in various construction applications, e.g., fill and landfill liners, after modifying its properties by mixing it with various admixtures, e.g., Das et al (1978), Lovell (1990, 1993), Kayabali and Bulus (2000), , Kumar and Stewart (2003a, b), Vaddu (2003, 2004), and Seals et al (1972). There is an ample of literature available on the structural, chemical, and mechanical properties of silty clays and sands amended with various admixtures (e.g., Odell et al, 1960;Sivapullaiah et al, 1996;Abeele, 1986;Chapuis, 1990;Pandian et al 1995;Mollins et al, 1996Mollins et al, , 1999Magistris et al, 1998;Kumar and Yong, 2002). However, studies on morphological analysis of PCC bottom ash-bentonite composite are scarce, if any.…”