Chemical composition of water from roofs in Gdansk, Poland

Stefan Tsakovski1, Marek Tobiszewski, Vasil Simeonov

  • 1Chair of Physical Chemistry, Faculty of Chemistry, University of Sofia, J Bourchier Blvd. 1, 1164 Sofia, Bulgaria. stsakovski@chem.uni-sofia.bg

Related Concept Videos

Waterproofing and Anti-Bacterial Admixtures in Concrete01:22

Waterproofing and Anti-Bacterial Admixtures in Concrete

Concrete's susceptibility to water absorption is due to the capillary action within the pores of its hydrated cement paste. This action draws water in, creating the need for waterproofing admixtures to prevent such penetration. The efficacy of these admixtures is contingent upon the water pressure, with variations arising from different conditions such as rain, capillary rise, or hydrostatic pressure in structures intended to hold water.
Waterproofing admixtures render concrete hydrophobic,...
Quality of Water01:19

Quality of Water

In concrete preparation, the quality of water is paramount as it affects the strength and durability of the concrete. Potable water is usually preferred; however, it must not have excessive sodium or potassium to prevent compromising the concrete's integrity. Water quality is typically evaluated based on impurities such as dissolved solids, chlorides, and sulfates, and its pH value is ideally between 6 and 8. Even slightly acidic natural water may be acceptable unless it contains harmful...
Testing Water Quality01:14

Testing Water Quality

When the quality of water for concrete preparation is uncertain, its impact on the setting time of cement and compressive strength of mortar is assessed by comparison with de-ionized or distilled water benchmarks. American Society for Testing and Materials (ASTM) C1602 requires the setting times to be within 90 minutes of the control, British Standard (BS) 3146:1980 allows a 30-minute variance in the initial setting, while British Standards European Norm (BS EN) 1008 specifies initial setting...
Cavity Drainage and Flashings in Masonry walls01:20

Cavity Drainage and Flashings in Masonry walls

Typically, a cavity wall consists of two wythes separated by a gap of at least 2 inches, which may contain insulation while still maintaining a minimum clear space of 1 inch to facilitate adequate drainage. Advanced methods like the insertion of a continuous drainage mat can further reduce this space while ensuring effective moisture expulsion.
Weep holes, strategically placed at the base of the cavity, are critical for draining accumulated water. These openings are created by leaving head...
Effect of Sea Water on Concrete01:22

Effect of Sea Water on Concrete

Concrete exposed to seawater can undergo degradation like the dissolution of ettringite and gypsum, increasing the material's porosity and decreasing its strength. In contrast, the crystallization of salts within the concrete's pores can cause expansion, particularly above the waterline where evaporation occurs. Nonetheless, this expansion only happens when seawater, enabled by the concrete's permeability, manages to infiltrate the structure.
Concrete in areas between tide marks, which undergo...
Water Cement Ratio01:28

Water Cement Ratio

The water-cement ratio is pivotal in defining concrete's quality. This ratio, a balance between the weight of water and cement in the mix, shapes the concrete's strength, durability, and resistance to environmental factors. As identified by Abrams’ law, less water in the mix equates to stronger concrete. However, water is essential not only for the chemical process of hydration but also for the concrete's workability and compaction. While hydration chemically binds water and cement, physical...