Impact of freeze–thaw weathering on integrity, internal structure and particle release from micro- and nanostructured cement composites

Abstract

Micro- and nanomaterials can i) reduce cement consumption in concrete, ii) improve durability of cement-based constructions and iii) modulate particle release.

Pore Structure as a Response to the Freeze/Thaw Resistance of Mortars

“…The authors in study [8] investigated the resistance of mortar to freeze/thaw cycles on the panels made of frost resistant brick applying the procedure that is prescribed in CEN/TS 772-22 [9], which is usually used for brick units. The authors in [10,11] treated their specimens according to RILEM-CDF, the authors in [12,13] applied a regime prescribed in ASTM C666 [14], the authors in [4] conducted tests according to EN 12371, which is applicable to the frost resistance measurements of natural stone, the authors in [15] used CEN/TS 12390-9, which is intended for the frost resistance determination of concretes, and the authors in [7] devised their own regime to simulate the freeze/thaw cycles.…”

“…In order to estimate mortar’s resistance to freeze/thaw cycles, researchers have been studying the influence of applied tests on various features and measured values: changes in the surface appearance of samples [8,13], changes in the compressive and flexural strength as well as dynamic modulus of elasticity [12,13,15,16], changes in the weight of the specimens [4,7,12], water absorption [15,16], pore structure and its changes during the cycles [10], and the number of freeze/thaw cycles the specimens can resist until complete disintegration [4,7]. During the freeze/thaw cycles, the surface of the mortar specimens becomes damaged, its compressive and flexural strength (as well as dynamic modulus of elasticity and weight) are decreased, and its water absorption is increased.…”

“…Within the term porosity or the pore system, it is important to distinguish gel pores, capillary pores, and macro pores of different sizes [15]. The capillary and macro pores are reported to be the most detrimental for the durability of a mortar [26].…”

“…The authors in [27], on the other hand, consider gel pores up to 0.0025 µm, capillaries from 0.1 to 10 µm, and macros larger than 10 µm. In [15], the pores are divided into groups according to their size, as follows: gel (up to 0.03 µm), capillary (0.03–10 µm), and macro (over 10 µm). The authors in [6] divided the pores into micro (up to 0.01 µm), meso (0.01–0.05 µm), and macro (0.05–1 µm) pores and cracks (over 1 µm).…”

Investigating the release of ZnO nanoparticles from cement mortars on microbiological models

“…In recent years, there is a growing concern about the safety of using NPs in cementitious composites. Thus, the amount of the research works increased substantially (Bräu et al 2012;Spinazzè et al 2016;Bossa et al 2017Bossa et al , 2019Diamond et al 2017;Miller et al 2017;Strokova et al 2018;Funk et al 2019;Torres-Carrasco et al 2019;Augustyniak et al 2020b). In Funk et al (2019) analyzed micro-and nano-components' release from cementitious composites containing TiO 2 and SiO 2 NPs after freeze-thawing.…”