Experimental study of recycling lightweight concrete with aggregates containing expanded glass

The focus is on the issue of waste management when constructing and recycling lightweight concrete (LWC) with aggregates containing expanded glass. The paper analyses the recycling of concrete from lightweight aggregates, and on the important issue of environmental and waste management. The characteristics of recycling LWC such as density, compressive strength and thermal conductivity are investigated, and compared with normal existing concrete from lightweight aggregates. The results indicate that it is possible to recycle lightweight concrete construction waste. The described method shows great possibilities for increasing the use of construction waste materials from LWC containing expanded glass, in order to benefit from better use of the available capacity from existing construction waste. The characteristics of density, compressive strength and thermal conductivity from the new recycled material were compared with normal existing concrete from lightweight aggregates, such as changes in dependency on the type and parts of waste as well as its new binding components. Thus, a new recycled material has been created with new characteristics of density, compressive strength and thermal conductivity, which is conform to the compressive strength class and rules on heat protection and energy efficiency use in buildings (SI OJ RS No. 42/2002). Laboratory density, compressive strength, and thermal conductivity tests results showed that LWC can be produced by the use of waste LWC with aggregates containing expanded glass. However, the use of waste LWC with aggregates containing expanded glass seems to be necessary for the production of cheaper and environmentally friendly LWC.     

Transitioning to sustainable production – part II: evaluation of sustainable machining technologies

This paper presents a case-study that highlights the importance of sustainable machining technologies in achieving sustainable development objectives. A technology evaluation was undertaken to understand the likely impacts of the use of technology on sustainability performance measures. The evaluation is more than an experimental method for supporting the design of technology and an instrument for supporting decision-making. It is also a tool for supporting technology policy and for encouraging its adoption and application in industry. More specifically, a sustainability evaluation of cryogenic and high pressure jet-assisted machining in comparison to conventional machining is examined. Sustainability performance measures refer to environmental impact, energy consumption, safety, personal health, waste management, and cost. The case-study refers to the machining of high-temperature Ni-alloy (Inconel 718). It is shown that tooling costs represent the major contribution to the overall production cost, which contradicts previous analyses, and that sustainable machining alternatives offer a cost-effective route to improving economic, environmental, and social performance in comparison to conventional machining.