Obituary: John F. Mullan, MD, 1925-2015: neurosurgery's modern statesman

Mortar joint deterioration is a significant concern in masonry structures, with water accumulation in the joints leading to damage from freeze-thaw cycles. The repeated expansion of water during freezing and its melting during thawing develop and propagate cracks in the masonry joints. Eventually, this leads to the spalling of mortar from the joints, loosening masonry units and weakening the structure. The deteriorated mortar joints are also vulnerable to moisture intrusion into the walls.
The...

Masonry, known for its strength, durability, and aesthetic versatility, encompasses construction with solid stone or man-made units like bricks, clay tiles, terra cotta, and concrete blocks, combined to form structures like walls, floors, and arches. These units are placed in a systematic fashion, known as coursing, and are bound together using mortar—a mixture typically made of water, cement, and sand.
The process of building with masonry is hands-on and can be executed with basic tools....

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...

The construction of masonry paving involves using materials such as bricks, stones, and concrete masonry units. These materials are chosen for their shape, color, strength, and resistance to abrasion and weathering. Masonry units can be installed dry on a thin layer of sand and a gravel base, or they can be embedded in mortar or asphalt on a concrete slab. For areas subjected to heavy vehicular loads, a rigid base layer of reinforced or unreinforced concrete is recommended. In contrast,...

Constructing a concrete masonry wall involves a series of steps designed to ensure durability, stability, and alignment. The construction starts with preparing the base, which includes cleaning the area where the wall will be erected. The next step involves spreading mortar where the first row of concrete blocks will be laid, typically starting at a corner section to help define the wall's boundaries.
Mortar application focuses on the face shells of the blocks, the sides that face outward,...

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...