Experimental study on sulfate erosion resistance of nano-CaCO₃ modified concrete

Abstract

In the saline soil environment of western China, the salts can corrode the ordinary cement concrete seriously, and the durability of concrete structure deteriorates gradually until it fails. This impedes the application of ordinary Portland cement concrete in this area. Aiming at the problem of the short service life of concrete in the harsh environment of western China, this study probes the performance of nano-CaCO<sub>3</sub> modified concrete in a sulfate environment. The durability of the concrete was evaluated by the apparent phenomena on the relative quality evaluation parameter, the relative dynamic elastic modulus evaluation parameter, and the comprehensive damage evaluation parameter. The microstructure of corroded products was investigated through scanning electron microscopy (SEM) to reveal the deterioration mechanism. The result shows that the addition of 1% nano-CaCO<sub>3</sub> can enhance the resistance of concrete to sulfate corrosion, and the service life of concrete structures will increase significantly.

Influence of Nano-CaCO₃ on the Strength and Fatigue Behavior of Concrete with 30% or 50% Recycled Coarse Aggregates

“…It can be seen that the sudden failure of RAC interface transition weakness can not be ignored in fatigue load, and incorporation of NC can effectively improve the N of RAC to a certain extent. As reported by Poudyal et al (2021) and Qiao et al (2022), this may be attributed to the nucleation and microcrack filling effects of NC. The effect of NC can compensate for some deficiencies in the microstructure level of RAC to improve the overall macroscopic structure, and thereby enhance the fatigue resistance of RAC.…”

“…According to the recommended value of recycled coarse aggregate replacement rate of high-rise buildings in Chinese Standard GB/T 25177-2010, the RCA replacement rates in RAC and NC-RAC are determined to be 30% and 50% by weight. It has been reported that the strength of concrete decreases significantly when the content of NC is higher than 2% (Poudyal et al 2021;Qiao et al 2022). In the experiment, the content of NC was set to 1% and 2% by weight.…”

“…When nano-CaCO 3 is used as the modifying concrete material, it can exert the filling effect, heterogeneous nucleation and the dilution effect. And it also reacts with C3S and promotes the hydration reaction rate of C3A to accelerate the formation of carboaluminate compounds (Diao et al 2022;Poudyal et al 2021;Qiao et al 2022;Supit and Shaikh 2014). In addition, nano-CaCO3 has a wide range of natural sources, simple artificial synthesis method and low preparation costs.…”

Experimental study on road piezoelectric energy harvesters' power generation performance under erosive environments

“…Therefore, this is the same as the adverse effect of the above hydration reaction on the power generation performance of piezoelectric transducers. As the strength of concrete increases, the internal stress continues to increase, and the deformation of the piezoelectric transducer is more restricted, hindering its power generation performance 23 . Finally, when the generated expansion stress exceeds the tensile strength of the concrete, defects begin to appear at the interface between the piezoelectric transducer and the cement paste, which is beneficial to the power generation performance.…”

“…As the strength of concrete increases, the internal stress continues to increase, and the deformation of the piezoelectric transducer is more restricted, hindering its power generation performance. 23 Finally, when the generated expansion stress exceeds the tensile strength of the concrete, defects begin to appear at the interface between the piezoelectric transducer and the cement paste, which is beneficial to the power generation performance. Among erosive products, ettringite is the primary cause of destruction.…”