Multifactorial study of macroscopic properties of solidified sludge. Part II: Porosity

Abstract

Investigations into the cement-based solidification of dredged sludge have been undertaken using a statistical analysis based on a fractional factorial experimental design. In Part I, the effects of cement content, type of cement, curing conditions and additives (lime, road binder, fly ash and silica fume) on unconfined compressive strength (UCS) before and after immersion in water, were studied. This paper examines the total porosity and the microstructure of the solidified sludge as well as the strength–porosity relationship. The total porosity values ranged from 37 to 56%, with a global variance of 2·2%. As the UCS, the total porosity and the pore size distribution were mainly influenced by the cement content and the curing conditions. With regard to the additives, lime, road binder and fly ash had significant effect, and the increasing of all additive contents reduced the total porosity. Dans le cadre d'un large programme de recherche sur la solidification de sédiments de drgage à base de ciment, la méthodologie des plans d'expériences a été utilisée afin de caractériser les propriétés des structures solidifiées. Dans la première partie de cet article, les effets de plusieurs facteurs (dosage et type de ciment, mode de stockage, dosages en chaux, liant routier, cendres voluantes, et fumée de silice) sur la résistance à la compression ont été analysés. Dans cette deuxième partie, nous nous intéressions à la porosité ainsi que la distribution poreuse. Les résultats montrent que la porosité totale vrie de 37 à 56% avec une variance globale de 2·2%. Le dosage en ciment etle mode de stockage semblent être les facteurs les plus prédomaints vis-à-vis de la porosité et la distribution poreuse. Quant à l'action des additifs, la chaux, le liant routier ainsi que les cendres volantes se sont révélés les plus significatifs.

Performance evaluation of commercial nanolime as a consolidant for friable lime-based plaster

“…The test started with drying the disk samples (D and E series) in a drying oven at 60 °C until the weight was consistent. As excessive drying temperature can alter microstructure of the lime based samples (Boutouil and Levacher, 2002), the temperature of the drying oven was carefully monitored. Dried samples were then placed in a desiccator and cooled at room temperature.…”

Strength of Chemically Stabilized Sewage Sludge—Some Inferences from Recent Studies

“…Some studies involving non-sewage sludge were not included in this study. For instance, refs [2,3] used sludge which was dredged from the seabed rather than produced by wastewater or sewage treatment. The sludge used in [2,3] is comprised mainly of silt and clay and has significantly lower liquid limit than typical sewage sludge.…”

“…It comprises mainly colloidal sediments containing organic material, microorganisms, toxic chemicals, and varying amounts of heavy metals. Sewage sludge differs significantly from dredged clay and silt, which are sometimes also termed "sludge" [2,3]. In general, sewage sludge has much higher organic content and plasticity index than dredged "sludge".…”