Effect of nano-calcium carbonate on early-age properties of ultra-high-performance concrete

Abstract

In this study, the effects of nano-calcium carbonate (CaCO3) addition on the early-age properties of ultra-high-performance concrete cured at simulated cold and normal field conditions were investigated. The nano-CaCO3 was added at rates of 0, 2·5, 5, 10 and 15% as a partial volume replacement for cement. Similar mixtures incorporating chloride- and non-chloride-based accelerating admixtures were also tested for comparison. Results indicate the high potential of nano-CaCO3 to accelerate the setting and hardening process of ultra-high-performance concrete through providing nucleation sites, increasing contact points and increasing the effective water-to-cement ratio. Although nano-CaCO3 exhibited a comparable or slightly lower accelerating effect to that of the chloride- and non-chloride-based accelerating admixtures, it brings a number of benefits to concrete production. These include the development of low-maintenance structures through eliminating the risk of steel corrosion induced by chloride-based accelerating admixtures, as well as a more environmentally friendly concrete through reducing the cement factor of ultra-high-performance concrete.

Review on concrete nanotechnology

“…An increasing number of studies on this issue have been reported in the last few years. Camiletti, Soliman, and Nehdi (2013) tested the effects of NCa on the early-age properties of ultra-high-performance concrete (UHPC) with addition of NCa at 0, 2.5, 5, 10 and 15% by weight of cement.…”

Radiopacity of Mineral Trioxide Aggregate with and without Inclusion of Silver Nanoparticles

“…Some authors observed that NPs improve both fluidity and workability as they influence the process of hydration and fill the empty spaces. 21,22 In addition, NPs provide these effects even when used at low levels. 23 The Ag NPs show high antibacterial efficacy and low toxicity to humans, 24,25 being studied in various dental applications, such as restorative material, 26 retrosealer, 27 and dental implants.…”

Effects of Nano‐CaCO3/Limestone Composite Particles on the Hydration Products and Pore Structure of Cementitious Materials

“…In recent years, nano-CaCO 3 has been introduced in concrete [18], and some studies have suggested a potential benefit of physical properties of nano-CaCO 3 on the development of cementitious system [19][20][21][22][23][24]. However, it is believed that the most important challenge in the nanocomposite research is to disperse properly the nanomaterials into the matrix [25,26].…”

“…Furthermore, due to the sophisticated surface structures of nanomicron composite particles, it can have a signi cant e ect on the hydration and microstructure of cementitious materials. Camiletti et al [20] found that nano-CaCO 3 accelerates the setting and hardening process of ultra-high-performance concrete through providing nucleation sites, increasing contact points, and increasing the e ective water-to-cement ratio. Yang et al [16] also believes that nano-CaCO 3 particles on the surface of LS can act as heterogeneous nuclei for cement paste, making the size of calcium hydroxide crystals smaller, leading to a denser microstructure.…”