Microstructural refinement of cement paste internally cured by polyacrylamide composite hydrogel particles containing silica fume and nanosilica

Concrete incorporating supplementary cementitious materials: Temporal evolution of compressive strength and environmental life cycle assessment

“…This improvement in strength can be attributed to the densification of the matrix microstructure due to the formation of C–S–H as a result of the reaction between the microsilica from SF and the CH produced during cement hydration [ 88 , 89 ]. An additional factor contributing to the improved packing density of concrete, which resists greater load per unit area and increases mechanical strength, is the filling impact of ultrafine silica fume particles [ [90] , [91] , [92] ]. At 28 days, SF10 exhibited a strength comparable to the control, with a slight increase of 2 % observed at 56 days.…”

Recent progress in superabsorbent polymers for concrete

“…These reductions are likely due to the ability of SRA molecules to simultaneously reduce the surface tension of fluid in the cement matrix as well as increase the fluid's viscosity [92]. When silica fume and nanosilica have been incorporated directly into SAP particles, overall absorption capacities have been observed at times to both increase [93] and decrease [94][95][96]. Additionally, the presence of silica fume in cementitious mixtures has been observed to increase the desorption rate of SAP particles [97]; as silica fume typically creates a finer pore structure, the authors suggested that its presence facilitated SAP desorption by increasing the capillary pressure of the matrix.…”

“…First, shear forces encountered during mixing will likely change the size distribution of SAP particles [87] as well as their sorption kinetics which are dependent on particle size and surface area [9,86]. Secondly, geometric confinement due to the presence of solids may interfere with the volumetric expansion of the hydrogel particles [93,[104][105][106][107].…”

“…Additionally, in real cementitious mixtures, the physical confinement imposed by the surrounding cement grains and aggregate solids may limit the free volumetric swelling of a SAP, especially for SAP particles with relatively low bulk modulus values such as compositions with a low covalent crosslink density [93,104,114]. Farzanian et al have experimentally demonstrated that enhancing mechanical pressure from zero (free swelling) to 3.4 kPa and hence, volumetric confinement, of a collective of SAP particles exposed to distilled water reduces its volumetric equilibrium swelling extent from 275 to only ten [105].…”

Development of high-performance self curing concrete using super absorbent polymer and silica fume additives

“…However, when silica fume was incorporated with SAPs, contradictory results with respect to strength after curing was reported. The study by Bose et al [10] reported an increase in mechanical properties while another study reported a decrease of the same [11]. The control of dosage of silica fume plays a dominant role in the development of superior mechanical properties in HPC.…”