Evaluation of the Contact Angle of Hydrophobised Lightweight-Aggregate Concrete with Sewage Sludge

Abstract

Abstract:The aim of the research presented in the paper was to evaluate the feasibility of using hydrophobic preparations based on organosilicon compounds for protection treatment of lightweight aggregates modified with municipal sewage sludge. Issues related to the wettability of the surface layer of hydrophobised lightweight-aggregate concrete supplemented with sewage sludge are discussed in the paper. The experimental part of the study is focused on the physical and mechanical characteristics of lightweight-aggregate concrete and the effect of two hydrophobic preparations on the contact angle of the material. The contact angle for lightweight concrete (θw) was determined as a function of time using one measurement liquid. The hydrophobic coatings in the structure of lightweight concrete modified with sewage sludge were shown using electron microscopy. The investigations demonstrated the effectiveness of hydrophobisation of porous lightweight concretes. On the hydrophobic surfaces, the contact angles decreased with time and depended on the preparations used. The results of the research confirm the possibility to produce lightweight aggregate-concretes modified with sewage sludge with appropriate surface protection against external moisture.

Sustainable low-carbon binders and concretes

“…They are water resistant, durable and can be utilized for the production of building mortars, dry mixtures for plaster, restoration works, as well as partitions and walls in wet rooms, for the formation of bulky elements of sanitary cabinets, for devices of self-leveling screeds under a floor. Particularly noteworthy is the use of composite gypsum binder for the manufacture of lightweight concrete -arbolite based on composite binders, organic fillers (up to 50-60 % of the volume) and chemical additives [21]. Blocks using composite binder based on gypsum, cement and superzeolite, as well as hemp as a filler are sustainable, heat resistant, humidity-free -and carbon negative.…”

Hydrophobisation of mortars containing waste polyurethane foam

“…Methyl-silicon resin (R) increased the frost resistance by 77-84%, while alkyl-alkoxysiloxane (A) raised it by 66-80% in relation to the reference samples. The layer of polisiloxane resin protected the surface against the infiltration of water, and consequently, against the destructiveness of ice [3,[9][10][11].…”

“…However, the resistance has not been determined after the frost resistance test, but the samples were dried to constant mass, and mass loss was determined. The surface free energy (SFE) was established by measuring the contact angle of the considered mortars [3,9,11]. For that purpose, a test stand consisting of a goniometer and a camera for capturing the images of 2 mm 3 drops placed on the sample surface with a micropipette [3,9] was used [15].…”

“…However, waste polyurethane foam can be a reason for increased wettability of mortars, hence after they have been prepared, a surface hydrophobisation should be considered. The purpose of our further research [3,[9][10][11] was the evaluation of the possibility of applying hydrophobising preparations based on silica-organic compounds in the protection of lightweight mortars and concrete with construction waste, as well as water and wastewater management.…”

Enhancing Functionality of Epoxy–TiO2-Embedded High-Strength Lightweight Aggregates

“…It is well known that TiO 2 is superior to other photocatalytic materials, such as ZnO, SnO 2 , Fe 2 O 3 , CuO, NiO, and CeO 2 , in its ability to remove NO x and SO x by the photo-decomposition principle under UV light irradiation [ 16 , 17 ]. In addition, the enhanced photodegradation performance of a cement-based composite by controlling the content of TiO 2 in the cement-based composite [ 18 ], the impregnation and coating of sodium silicate on LWAs to provide self-healing properties [ 19 ], the improved skid-resistance of LWAs by controlling aggregate morphology through micro-surfacing [ 20 ], the hydrophobicity control of LWAs modified with sewage sludge [ 21 ], and the embedment of phase change materials into LWAs to improve thermal energy storage characteristics and reduce damage mitigation [ 9 , 22 ] have been studied. Although various studies are being conducted to develop artificial LWAs that can increase the strength and durability of aggregates and exhibit various functions, there has been minimal progress in the development of high-quality multi-functional artificial LWAs that can be applied to high-rise and large-scale buildings.…”