No description available.

No description available.

No description available.

No description available.

The poor durability performance of reinforced concrete structures is a major problem facing the construction industry throughout the world. It IS estimated that more than $200 billion will be required to repair and rehabilitate deteriorated concrete structures in the USA. Similarly, it is estimated that more than £2 billion will be needed to repair deteriorated concrete structures in the UK Also, considerable resources have to be diverted towards the repair of deteriorated concrete structures in the countries along the Arabian Gulf. Concrete deterioration, worldwide, is mainly attributed to reinforcement corrosion that is caused by chloride ions. However, the effect of other ions, particularly sulfates, on reinforcement corrosion has not been adequately studied. Reinforced concrete structures in marine environments and those built in ‘sabkha' soils are exposed to both chloride and sulfate salts The combined presence of these two ions may accelerate reinforcement corrosion. Cement chemistry may also Significantly influences the mechanisms of reinforcement corrosion. The quantity of C3A and the alkali content of cement effects its chloride-binding capacity. While considerable research has been conducted on the effect of C3A content of cement on its chloride-binding and reinforcement corrosion, meagre data exist on the effect of cement alkalinity on chloride-binding, while no study has been conducted to evaluate the effect of cement alkalinity on reinforcement corrosion.

No description available.

No description available.

No description available.

This research examines the environmental parameters associated with the production and delivery of building materials in the U.K. in 1991. Using primary data supplied from commercial sources, an eco-profile is produced for each material by calculating the gross inputs of energy and raw materials and gross outputs of solid waste, air and water emissions. The production sequences are traced from raw materials in the ground through to the final product and extend to include transport operations and the production and delivery of fuels and ancillary materials. The results are used to complete eco-profiles for the construction of a three bedroom bungalow house and a four bedroom two storey detached house. It is shown that per square metre of floor space, the construction of the two storey detached house produces considerable reductions in the burdens on the enviromnent. Eco-profiles are used to compare the environmental burdens associated with alternative building materials. The effect of alternative building materials on the eco-profiles of house construction is discussed. It is shown that significant reductions in the gross inputs and outputs maybe made by substituting dense concrete blocks for clay bricks.

The work carried out in this thesis outlines some of the problems associated with abrasive wear in machines and other mechanical equipment used to excavate or process natural rock material. It has been stated that if the problems associated with abrasion are to be better understood, then a sound knowledge of the abrasive potential of rocks is essential. A number of common wear mechanisms are described together with existing hardness and abrasive tests. The author has investigated rock hardness and abrasiveness by the use of existing methods and subsequently, developed new correlated with the well tests which can be established methods of determining physical and mechanical properties of rock. A project on hard rock drilling has been conducted to determine the rate of wear on expensive diamond impregnated coring drill bits. A detailed investigation which involved the design and manufacture of special measuring equipment to accurately measure and record changes in the profile shape of the bit during its life span. This has permitted a study of the wear characteristics related to the various drilling parameters employed. A collaborative project was carried out with DeBeers, UK, to attempt to discover methods of predicting the rate of specific wear on diamond impregnated saw blades and the cutting forces required with the sawing of hard stone materials. This project has led to a new statistical approach to the analysis of the acquired test data for this purpose. A number of case histories have been discussed and recommendations made. As a result of these investigations together with the work covered in this thesis, the author has developed two new abrasive tests. These tests can be used to test materials such as unconsolidated rocks which otherwise, could not be satisfactorily tested by the established tests already in existence. The new tests have been tried and proved by correlating the test data by combining multiple regression analysis with the results obtained from physical and petrological rock property tests with actual rock cutting data. Conclusions have been drawn and recommendations for future work suggested.