Outbreak of Silicosis in Workers Producing Artificial Stone Skirting Boards: A Novel Application of Silica-Based...

Quarrying is the process of extracting stone from a quarry, where specialized techniques are employed to remove large blocks of stone safely and efficiently. This process can involve controlled explosions or more precision-oriented methods such as cutting and drilling.
One common method involves using a diamond belt saw to cut large blocks from the quarry face. These blocks can be about 50 feet long and 12 feet high. After the initial vertical cut, drilling is performed at the base of the...

The process of manufacturing concrete masonry units begins by mixing stiff concrete composed of Portland cement, aggregates, and water. This mixture is then poured into metal molds. To ensure the concrete settles uniformly and to avoid separation of its components, the mixture in the molds is subjected to vibration. Shortly after, the still-wet blocks are removed from the molds and placed on racks.
These wet blocks are then transported for curing, which can occur in one of two environments: a...

The alkali-aggregate reaction in concrete involves natural siliceous minerals in aggregates reacting with alkaline hydroxides derived from cement alkalis. This reaction forms an alkali-silica gel that absorbs water, swells, and increases in volume, which is confined by the surrounding cement paste, creating internal pressures that crack and disrupt the concrete. The extent of expansion and damage can be partly attributed to the alkali-silica reaction's osmotic hydraulic pressure and the...

Deleterious substances in aggregates can be detrimental to the quality and durability of concrete. These substances include organic impurities like loam, which interfere with cement hydration and are usually present in the sand. These prevent a good bond between aggregate and cement paste. Organic impurities can be detected using the colorimetric test, where the darkness of a solution after agitation indicates the level of organic content.
Another type of impurity is clay and fine material that...