Jawaharlal Nehru Technological University Hyderabad B.Tech II BUILDING MATERIALS, CONSTRUCTION AND PLANNING Previous Question Paper (March 2022 - R13)

Quarrying with hand tools is a traditional method suitable for soft rocks or small-scale operations where mechanical equipment is not feasible. The process involves the following techniques:

1. Wedging: This is the most common method for stratified rocks. Narrow holes are drilled along the natural bedding planes of the rock at regular intervals. Steel wedges and feathers (thin iron plates) are inserted into these holes and struck with a hammer. The pressure generated splits the rock block along the desired line.
2. Heating: This method is used for rocks that are not easily split by wedges. A fire is built on the surface of the rock, causing the top layer to expand due to heat. As the rock expands, it separates from the cooler, underlying mass, allowing it to be pried off using crowbars.
3. Excavation: For very soft rocks or weathered stone, hand tools like picks, shovels, and crowbars are used to directly dig and pry the material out from the quarry face.

These methods are labor-intensive and slow but are cost-effective for small-scale projects or when the rock is easily accessible and not overly hard.

Plastic emulsion paints are water-based decorative coatings that use synthetic resins (such as acrylic or vinyl) as binders. They are known for their quick drying time, excellent washability, durability, and low odor compared to oil-based paints. In building construction, they are primarily used for interior and exterior wall finishes, providing a smooth, matte, or satin finish that is resistant to fungal growth and fading.

To prepare the commercial product for application at the site, follow these steps:

1. Surface Preparation: Ensure the wall surface is clean, dry, and free from dust, grease, or loose particles. Apply a coat of primer if necessary to ensure better adhesion.
2. Dilution: Emulsion paints are typically supplied in a thick consistency. They must be thinned with clean, potable water. The manufacturer's recommended ratio (usually 400-500 ml of water per liter of paint) should be strictly followed.
3. Mixing: Pour the measured water into the paint container gradually while stirring continuously with a clean wooden or plastic stirrer. The goal is to achieve a uniform, lump-free consistency suitable for brush or roller application.
4. Straining: After mixing, it is recommended to strain the paint through a fine mesh or muslin cloth to remove any skin or impurities before application.