Utilization of siliceous–aluminous fly ash and cement for solidification of marine sediments

Utilization of Sandy Soil as the Primary Raw Material in Production of Unfired Bricks

“…is phenomenon is mainly attributed to the pore-filling effect of GGBS due to the spherical shape preventing water entry [36]. With the activation of quicklime and gypsum, the pozzolanic reaction of GGBS and hydrate reaction of cement are accelerated, which produces more C-S-H and ettringite, so the cement-soil mixes stabilized by GGBS, quicklime, and gypsum become much more compact than those without other stabilizers.…”

“…e , it can be observed that the peaks of C-S-H and ettringite in specimens increase as the curing period increases, which is in good agreement with SEM observation results mentioned previously, which is why the performance of 90-day cured C8GG10Q5G2 specimens are better than that of both 7-day and 28-day cured C8GG10Q5G2 specimens. It can be generally found that the higher the quantity of C-S-H and ettringite the better performance of brick specimens is [36].…”

“…During the freezing/thawing cycles, the pore water changes into ice, and these ices can displace sandy soil particles, disrupting the interlocking of sandy soil particles, dilating the pore volume, and increasing microcracks' size. However, the increased pore volume and propagation of microcracks through the interfacial transition zone between paste and aggregates cannot fully recover due to the existence of cohesion in sandy soil particles at the time that the ices melt [36,37]. erefore, the cyclic thawing/freezing process can reduce the compressive strength and weight of the brick specimens.…”

Green remediation and recycling of contaminated sediment by waste-incorporated stabilization/solidification

“…Nevertheless, the contaminated marine sediments interfered with the chemistry of cement hydration, compromising the effectiveness of metal stabilization and development of compressive strength in the cementitious materials (Limeira et al, 2010;Wang et al, 2013). The presence of organic matter enhanced calcium complexation and pH buffering capacity that hindered the cement hydration and pozzolanic reactions , whereas soluble chloride and sulfate salts in marine sediments led to undesirable metal mobility (Zentar et al, 2012;Zhao et al, 2013). Moreover, heavy metals resulted in delayed setting and weak early strength via metal doping and isomorphic substitution in the hydrated and crystalline phases (Gollmann et al, 2010;Pandey et al, 2012;NavarroBlasco et al, 2013).…”

“…It was suggested that the mechanical strength of stabilization/ solidification could be improved via the pozzolanic reactions and pore filling in the structure by the addition of fly ash (Zentar et al, 2012;Tomasevic et al, 2013; and/or ground seashells (Lertwattanaruk et al, 2012;Moon et al, 2013). The fly ash contained high contents of glassy silica and alumina, whereas ground seashells were calcium carbonate-rich kitchen waste, thus they could assist the formation of cementitious compounds.…”