Effect of high temperature on strength and microstructural properties of cemented paste backfill

Abstract The main purpose of this research is to investigate the influence of high temperatures on the strength and microstructure (e.g. pore structure, porosity) of cemented paste backfill (CPB) through a series of experimental tests. A laboratory experimental setup allowing the simulation of various high-temperature conditions is developed. Different types of CPB specimens are exposed to different high temperatures (100, 200, 400 and 600 °C). The strength, porosity, pore size distribution and water absorption of these CPB specimens are then evaluated by laboratory tests. Thermogravimetric and differential thermal analyses are also performed to study the thermal behaviour of the CPBs exposed to high temperatures. The results show that high temperatures have a significant effect on the properties of CPBs. Generally, increasing temperatures up to 200 °C leads to higher strength in most types of CPB studied. The porosity and pore size distribution of the CPBs change only slightly. Above 200 °C, the temperature reduces the strength of the CPBs. The most notable strength decrease takes place at exposure temperatures exceeding 400 °C. The significant decrease of the strength of the CPB is accompanied by a significant change in the microstructure (porosity, pore size distribution, mineral phases). Moreover, the effect of high temperatures on the strength and microstructure of CPBs depends on the water/cement ratio (w/c ratio) and the tailings type.

[1]  Ulrich Schneider,et al.  Concrete at High Temperatures -- A General Review* , 1988 .

[2]  Mamadou Fall,et al.  Modeling the effect of sulphate on strength development of paste backfill and binder mixture optimization , 2005 .

[3]  S. Venecanin.  THERMAL INCOMPATIBILITY OF CONCRETE COMPONENTS AND THERMAL PROPERTIES OF CARBONATE ROCKS , 1990 .

[4]  Chiara F. Ferraris,et al.  SERVICE LIFE PREDICTION BASED ON SORPTIVITY FOR HIGHWAY CONCRETE EXPOSED TO SULFATE ATTACK AND FREEZE-THAW CONDITIONS , 2002 .

[5]  Ferri P. Hassani,et al.  Strength development in underground high-sulphate paste backfill operation , 2001 .

[6]  Robert J. Mitchell,et al.  Model studies on cemented tailings used in mine backfill , 1982 .

[7]  N. Martys,et al.  Sorption of Water in Mortars and Concrete , 1996 .

[8]  C. Karr.  Analytical methods for coal and coal products , 1978 .

[9]  J. Sercombe,et al.  Permeability and pore structure evolution of silicocalcareous and hematite high-strength concretes submitted to high temperatures , 2001 .

[10]  Nicolas Lequeux,et al.  Elastic properties of high alumina cement castables from room temperature to 1600°C , 1999 .

[11]  Nagaratnam Sivakugan,et al.  Study of Drainage Through Hydraulic Fill Stopes using Method of Fragments , 2006 .

[12]  Kristian Dahl Hertz,et al.  Limits of spalling of fire-exposed concrete , 2003 .

[13]  L. M. Amaratunga,et al.  Development of a high modulus paste fill using fine gold mill tailings , 1997 .

[14]  C. Hall,et al.  Water sorptivity of mortars and concretes: a review , 1989 .

[15]  F. W. Brackebusch,et al.  Basics of paste backfill systems , 1995 .

[16]  Chi Sun Poon,et al.  Impact of high temperature on PFA concrete , 2001 .

[17]  F. Glasser,et al.  Thermal stability and decomposition mechanisms of ettringite at <120°C , 2001 .

[18]  Edward J. Garboczi,et al.  Digital simulation of the aggregate–cement paste interfacial zone in concrete , 1991 .

[19]  O. Wallevik,et al.  Microstructure and microchemistry of the paste-aggregate interfacial transition zone of high-performance concrete , 1998 .

[20]  Š. Hošková,et al.  Effect of temperature on porosity of concrete for nuclear-safety structures , 2001 .

[21]  Mamadou Fall,et al.  Mix proportioning of underground cemented tailings backfill , 2008 .

[22]  Chi Sun Poon,et al.  Experimental study of micro/macro crack development and stress-strain relations of cement-based composite materials at elevated temperatures , 2004 .

[23]  Gabriel A. Khoury,et al.  Compressive strength of concrete at high temperatures: a reassessment , 1992 .

[24]  Wei Sun,et al.  Compressive strength and pore structure of high-performance concrete after exposure to high temperature up to 800°C , 2000 .

[25]  P. Monteiro,et al.  The aggregate-mortar interface , 1985 .

[26]  Ayhan Kesimal,et al.  The effect of desliming by sedimentation on paste backfill performance , 2003 .

[27]  V. Kodur,et al.  Stress-strain curves for high strength concrete at elevated temperatures , 2004 .

[28]  P. Grattan-Bellew,et al.  MICROSTRUCTURAL INVESTIGATION OF DETERIORATED PORTLAND CEMENT CONCRETES , 1996 .

[29]  Kousick Biswas,et al.  REVIEW OF CURRENT HIGH DENSITY PASTE FILL AND ITS TECHNOLOGY , 2002 .

[30]  P. L. Pratt,et al.  Quantitative characterization of the transition zone in high strength concretes , 1988 .

[31]  N. Richard.  Structure et proprietes elastiques des phases cimentieres base de mono-aluminate de calcium , 1996 .

[32]  Nagaratnam Sivakugan,et al.  Emplaced Geotechnical Characteristics of Hydraulic Fills in a Number of Australian Mines , 2006 .

[33]  Tikou Belem,et al.  A contribution to understanding the hardening process of cemented pastefill , 2004 .

[34]  F. S. Rostásy,et al.  Changes of pore structure of cement mortars due to temperature , 1980 .

[35]  Long T. Phan,et al.  International Workshop on Fire Performance of High-Strength Concrete, NIST, Gaithersburg, MD, February 13-14, 1997, Proceedings | NIST , 1997 .

[36]  Jianzhuang Xiao,et al.  Study on concrete at high temperature in China--an overview , 2004 .