Comminution and sizing processes of concrete block waste as recycled aggregates.

Due to the environmental impact of construction and demolition waste (CDW), recycling is mandatory. It is also important that recycled concrete aggregates (RCA) are used in concrete to meet market demands. In the literature, the influence of RCAs on concrete has been investigated, but very limited studies have been conducted on how the origin of concrete waste and comminution processes influence RCA characteristics. This paper aims to investigate the influence of three different comminution and sizing processes (simple screening, crushing and grinding) on the composition, shape and porosity characteristics of RCA obtained from concrete block waste. Crushing and grinding implies a reduction of RCA porosity. However, due to the presence of coarse quartz rounded river pebbles in the original concrete block mixtures, the shape characteristics deteriorated. A large amount of powder (<0.15 mm) without detectable anhydrous cement was also generated.

Is the physician office the wild, wild west of health care?

Elective, office-based surgery has captured the interest of consumers and, more recently, the attention of state health care regulatory agencies. In most states today, patients can undergo cosmetic surgery, liposuction, endoscopy, colonoscopy, microlaparoscopy, and various other procedures requiring sedation or anesthesia in physician offices even though no regulatory safeguards that would ordinarily benefit patients in accredited or licensed facilities exist. Media accounts of deaths and serious injuries associated with liposuction and anesthesia performed in physician offices resulted in legislative and regulatory initiates, such as those in California and New Jersey. Increased regulatory oversight, changes in patterns of reimbursement, and greater consumer awareness of safety and quality-of-care issues should aid in reducing the risks of office-based surgery.