ABSTRACT
Radical Concrete Technology. Edited by R K Dhir and P C Hewlett. Published in 1996 by E & FN Spon, 2-6 Boundary Row, London SE1 8HN, UK. ISBN 0 419 21480 1. ABSTRACT. This study was done for the company manufacturing prestressed high strength concrete pipe piles. Strength tests were made for autoclaved cement-ground sand pastes and concrete with ground sand. XRD and SEM analyses were also made to clarify the effect mechanism of the ground sand on cement hydration while autoclaved. Manufacture experience of prestressed high strength concrete pipe piles with the strength of 80N/mm2 was briefly introduced using ground sand to equally replace 30% cement in a factory. Key Words: Autoclaving, High-strength concrete, Ground sand Prof. Huang Shi-Yuan is honorary director of Research Lab of Material Engineering, Shanghai Institute of Building Materials, China. He is specialised in the durability of concrete; frost resistance, salt scaling and corrosion, the technology of pumping concrete and winter concreting. He is now a member of Science and Technical Committee of China National Admministration of Building Materials Industry. Mr Yang Quan-Bing is a lecturer in Cement and Concrete Technology, Shanghai Institute of Building Materials. His main research aspects include salt scaling of concrete, chloride diffusion through concrete and repairing materials. Mr Wang Zhan-De is an associate professor, SIBM. He Yiao-Hui is a manager and also an engineer of Hongji Concrete Pipe Piles Company.
INTRODUCTION It is well known that the Ca(OH)2 released by hydration of C3S in cement can react with quartz powder to form more or less crystallized CSH at elevated temperatures, for example 170°C [1]. Therefore a good concrete can be made by replacing part of cement with ground quartz sand by autoclaving. At present, in China a great number of plants are producing prestressed concrete pipe piles, among which most are prestressed highstrength concrete (PHC) ones (concrete strength >80 N/mm2) produced by autoclaving. However, they were made with ordinary Portland cement concrete without addition of any blended materials until the present study was carried out. Since those plants have been furnished with autoclave, why don’t we try to make concrete with ground quartz sand or ordinary river sand to save cement, energy comsumption and cost of the pipe piles?
