Influence of quartz powder and silica fume on the performance of Portland cement

Abstract

Supplementary cementitious materials interact chemically and physically with cement, influencing the formation of hydrate compounds. Many authors have analyzed the filler and pozzolanic effect. However, few studies have explored the influence of these effects on hydration, properties in the fresh and hardened states, and durability parameters of cementitious composites separately. This study investigates the influence of the replacement of 20% of Portland cement for silica fume (SF) or a 20-µm medium diameter quartz powder (QP) on the properties of cementitious composites from the first hours of hydration to a few months of curing. The results indicate that SF is pozzolanic and that QP has no pozzolanic activity. The use of SF and QP reduces the released energy at early times to the control paste, indicating that these materials reduce the heat of hydration. The microstructure with fewer pores of SF compounds indicates that the pozzolanic reaction reduced pore size and binding capability, resulting in equivalent mechanical properties, reduced permeability and increased electrical resistance of the composites. SF and QP increase the carbonation depth of the composites. SF and QP composites are efficient in the inhibition of the alkali-aggregate reaction. The results indicate that, unlike the filler effect, the occurrence of pozzolanic reaction strongly influences electrical resistance, reducing the risk of corrosion of the reinforcement inserted in the concrete.

Performance and Cost-Effectiveness of Short Pitch-Based Carbon Fiber Reinforced Mortar Composite

“…A superplasticizer allows for a substantial reduction in the amount of mix water and thereby decreases the capillary porosity of the mortar composite [ 18 , 56 ]. Moreover, silica fume contributes to decreasing the capillary porosity of cement composites [ 68 , 69 ] through its micro-filling ability and pozzolanic activity. In addition, it improves the interfaces of sand particles and carbon fibers [ 70 , 71 ] due to pore filling.…”

Effect Of Quartz Particle Size and Cement Replacement on Portland Limestone Cement properties

“…This increased water requirement for normal consistence of the cement blended with QP compared with the control could be due to the high surface area of the QP [27,46] as well as the diminution of the clinker content by cement replacement according to Waziri and Olubajo [46] . Other reasons for increased water demand include excess silica content in the cement matrix [24] and formation of nucleation sites for CSH precipitation [47] .…”

“…Kadri et al [23] observed that quartz with diameter between 20 µm and 25 µm did not exhibit pozzolanic activity and was considered a filler. The inclusion of fillers as one of the drivers for sustainability in the cement industry could provide economic, ecological and technical benefits as a result formation of more CSH despite clinker diminution [24][25][26][27][28] .…”

Seawater as Alkali Activator in Fly Ash Based Geopolymer

“…External source of CSH can increase the compressive strength of resulting mortar (Kunther, W., et al, 2017). There are several attempts to increase C-S-H by addition of compound that contains calcium (Ca), silica (Si) such as silica fume and calcium hydroxide nanoparticles (Tavares, L.R.C. et al, 2020;Camerini, R., et al, 2022), or CSH in various forms such as nano-calcium silicate hydrate, highly crystalized C-S-H Particles, and calcium silicate hydrate seeds (Zhu, S., et al, 2019;Wang, Y., et al, 2020;Alzaza, A., et al, 2022).…”