Use of crystalline waterproofing to reduce capillary porosity in concrete

Abstract

The use of different technologies have contributed to the increase in durability facing the aggressive agents that damage the concrete structures. Therefore, it is possible to reduce the capillary porosity in concrete lowering the ratio water/binder; using pozzolan, hydrophobic or waterproofing products in the mixture; applying hydrophobic products or waterproofing in the concrete surface; replacing pure cements for compounds cements, pozzolanic cements or cements with blast furnace slag; among other actions. The waterproofing has the function to prevent the water or fluid passage in liquid or steam state, thereby protecting structures. The waterproofing creates a barrier when coating is applied to close surface pores with the aim of preventing the water pervasion by any transport mechanism. This paper has evaluated the use of crystalline waterproofing as admixtures, as well as a coating, sanding and no-sanding, in order to know the benefits it can bring to the concrete water absorption, comparing their performance with other concretes with or without silica fume admixture. Developed tests were: total absorption, under pressure water penetration (30 kPa) and compressive strength test. The results have showed that the silica fume admixture is more efficient than the analyzed crystalline waterproofing, as it has contributed to the compressive strength increase and decrease of water absorption and penetration. The crystalline waterproofing admixture has contributed to compressive strength increase; however, there was also an increase in the absorption and penetration. On the other hand, the coating waterproofing has not influenced the compressive strength, but reduced absorption and penetration when sanded.

Use of Secondary Crystallization and Fly Ash in Waterproofing Materials to Increase Concrete Resistance to Aggressive Gases and Liquids

“…Research on secondary crystallization in cement composites has previously been dealing with the sealing of pore structures and sealing cracks. e benefits of utilisation of crystalline admixtures are well demonstrated in previously published studies [25][26][27][28][29][30]: however, improving the properties of concrete remains an important task even today [19]. Improving the durability of cementitious composites helps extend their longevity, thereby reducing repair costs associated with moisture damage of concrete structures [31].…”

Integration of Anhydrous Sodium Acetate (ASAc) into Concrete Pavement for Protection against Harmful Impact of Deicing Salt

“…32 Also, it is believed that silicon and sodium, which were also present in this material, will react with calcium hydroxide present in the concrete, in presence of water, to form silica gel that adheres to the walls of the pores. 43,44 This gel will develop into solid crystals after its hydration. The structure of crystals formed from the aforementioned reactions can be recognized in the SEM micrographs in Fig.…”

Os Efeitos De Diferentes Aditivos Cristalizantes Nas Propriedades Do Concreto No Estado Fresco E Endurecido

“…De acordo com os resultados apresentados no trabalho, para o traço com maior consumo de cimento o aditivo cristalizante testado melhorou a resistência do concreto à compressão em 27,2% quando comparado ao traço sem aditivo. Já em outro estudo desenvolvido por Cappellesso et al (2016), o traço dosado com aditivo cristalizante obteve resistência à compressão 16% superior ao traço sem aditivo. • No estado fresco do concreto, os aditivos cristalizantes causaram efeitos distintos, principalmente no abatimento e tempo de inicio de pega.…”