Green and early age compressive strength of extruded cement mortar monitored with compression tests and ultrasonic techniques

Knowledge about the early age compressive strength development of cementitious materials is an important factor for the progress and safety of many construction projects. This paper uses cylindrical mortar specimens produced with a ram extruder to investigate the transition of the mortar from plastic and deformable to hardened state. In addition, wave transmission and reflection measurements with P- and S-waves were conducted to obtain further information about the microstructural changes during the setting and hardening process. The experiments have shown that uniaxial compression tests conducted on extruded mortar cylinders are a useful tool to evaluate the green strength as well as the initiation and further development of the compressive strength of the tested material. The propagation of P-waves was found to be indicative of the internal structure of the tested mortars as influenced, for example, by the addition of fine clay particles. S-waves used in transmission and reflection mode proved to be sensitive to the inter-particle bonding caused by the cement hydration and expressed by an increase in compressive strength.

[1]  Surendra P. Shah,et al.  Properties of Early-Age Portland Cement Mortar Monitored with Shear Wave Reflection Method , 2004 .

[2]  D. Chung,et al.  Effect of methylcellulose admixture on the mechanical properties of cement , 1996 .

[3]  A. P. Hibbert,et al.  Correlation between cube strength, ultrasonic pulse velocity and volume change for oil well cement slurries , 1989 .

[4]  John S. Popovics,et al.  Using Ultrasound to Monitor Stiffening Process of Concrete with Admixtures , 2000 .

[5]  Surendra P. Shah,et al.  Processing Effects in Cementitious Composites: Extrusion and Casting , 2003 .

[6]  P. Richard,et al.  Superplasticizer effects on setting and structuration mechanisms of ultrahigh-performance concrete , 2001 .

[7]  Surendra P. Shah,et al.  Determination of Early Age Mortar and Concrete Strength by Ultrasonic Wave Reflections , 2003 .

[8]  Surendra P. Shah,et al.  Temperature effects on strength evaluation of cement- based materials with ultrasonic wave reflection technique , 2005 .

[9]  R. H. Elvery,et al.  ULTRASONIC ASSESSMENT OF CONCRETE STRENGTH AT EARLY AGES , 1976 .

[10]  S. Shah,et al.  Nondestructive measurement of concrete strength gain by an ultrasonic wave reflection method , 2003 .

[11]  Nicholas J. Carino,et al.  Properties of concrete at early ages , 1989 .

[12]  F. Cohen Tenoudji,et al.  Mechanical properties of cement pastes and mortars at early ages: Evolution with time and degree of hydration , 1996 .

[13]  Peter V. Coveney,et al.  Ultrasonic measurements on hydrating cement slurries: Onset of shear wave propagation , 1995 .

[14]  Jan Skalny,et al.  Materials science of concrete , 1989 .

[15]  Colin M. Sayers,et al.  Propagation of ultrasound through hydrating cement pastes at early times , 1993 .

[16]  Jean-Yves Delenne,et al.  Mechanical behaviour and failure of cohesive granular materials , 2004 .

[17]  Zhihui Sun,et al.  Early Age Microstructure Of Portland Cement Mortar Investigated By Ultrasonic Shear Waves And Numerical Simulation , 2005 .

[18]  Jan Byfors,et al.  Plain concrete at early ages , 1980 .