Date of Award


Document Type

Master Thesis

Degree Name

Master of Science


Chemical & Process Engineering

First Advisor

Mr. Noel Duffy


A national flow model for concrete was developed using the framework of material and energy flow analysis. Using this framework, the Irish concrete material and energy cycles for the year 2007 were constructed by firstly analysing the material life cycle of concrete which consists of the three phases of production (including extraction of raw materials and manufacture of cement), usage into stock (ready-mix and other concrete products), and waste management. In this year, approximately 35Mt of raw materials were extracted to produce both 5Mt of cement and 33Mt of concrete, with 4.5Mt of cement going into the production of concrete. By comparison the concrete waste produced in that year was minimal at only 0.3Mt. Next, the embodied energy of Irish construction concrete was determined with the focus being on energy used in the extraction of aggregates, in the manufacture of cement and in the production of concrete together with the associated transport energy, in order to complement the concrete material flow for the same year. In the year of study approximately 25PJ of energy was embodied in construction concrete with 3.3PJ of energy being used in the extraction of aggregates, 15.9PJ in the manufacture of cement, 0.2PJ in the mixing/blending in the production of construction concrete products and 5.6PJ in the transport of these construction concrete products. The total materials and energy requirements of the roads infrastructure and residential concrete construction sectors were also assessed to determine the impact of these construction sectors on flows into the economy. In 2007 approximately 4PJ of energy was used in the production of 10Mt of materials, in their associated transport and in the construction activities of road infrastructure. In the same year, the residential sector consumed 52PJ in the production of approximately 34Mt of materials for the construction of concrete dwellings. 18Mt of construction and demolition waste was produced in Ireland in the year under study with soil and stones constituting 14Mt of this waste. The significance of these flows is intertwined with the existence of “ghost estates” in the residential sector and the cumulative consumption of material and energy in Ireland’s “boom” years. The build up of construction stock in the Irish economy will have implications for future construction and demolition waste flows when the majority of stock constructed in the last decade reaches its end of life or is prematurely “retired”. The regular application of material and energy flow analysis as an information tool informing the Irish construction sector and the Irish governmental departments would facilitate the development of policies in relation to the sustainable use of resources and to the effective management of construction and demolition waste.

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