Research On The Loughness Of Emulsified Asphalt Cement Mortar

Based on summarizing the characterization methods and influence factors on thetoughness of polymer modified cement mortar, the toughness characterization methodsuitable for emulsified asphalt cement mortar was analyzed comparatively. The effects ofdifferent factors (mix proportion, air content and temperature) on the toughness of emulsifiedasphalt cement mortar were studied. The influence of different factors on the toughness ofemulsified asphalt cement mortar was analyzed from micro and macro perspectives by themeans of theoretical calculation and microscopic analysis. The mechanism of temperature onthe toughness of emulsified asphalt cement mortar was explained, and the recommendedrange for the key parameters of the mix proportion of emulsified asphalt cement mortar basedon the toughness was proposed.Firstly, the advantages and disadvantages of characterizing the toughness of emulsifiedasphalt cement mortar such as fracture energy or indentation energy or the ratio ofcompressive strength to flexural strength were compared in this paper, and the fracture energywas preferred to characterize the toughness of emulsified asphalt cement mortar. Secondly,the toughness development of different mB/mC (mass ratio of asphalt to cementitious material,referred to as the“the ratio of asphalt to binder”), mW/mC (mass ratio of water to cementitiousmaterial, referred to as the“the ratio of water to binder”), air contents and temperatures ofemulsified asphalt cement mortar were experimented. The results indicated that, with theincrease of the ratio of asphalt to binder, the discontinuous phase of asphalt gradually becamecontinuous phase, the thickness of asphalt film gradually increased, which led to the increaseof the toughness of emulsified asphalt cement mortar. With the increase of the ratio of waterto binder, the toughness of emulsified asphalt cement mortar increased firstly but thendecreased, and the maximum the ratio of water to binder was 0.49. With the increase of aircontent, the toughness of emulsified asphalt cement mortar reduced gradually. When thetemperature was above 20℃, the toughness of emulsified asphalt cement mortar declinedsignificantly with the increase of temperature; the higher the ratio of asphalt to binder, the greater the reduction of the toughness. When the temperature was below 20℃, the toughnessof emulsified asphalt cement mortar increased obviously firstly and then decreased gradually;the higher the ratio of asphalt to binder, the greater the improvement of the toughness. Inaddition, through analyzing the microstructure of mortar specimens by SEM, and discussingthe mechanism of temperature on the mortar toughness, the mechanism for the temperatureeffecting on the toughness of asphalt and on the toughness of emulsified asphalt cementmortar was proposed. Finally, based on the results, a reasonable range of the key parametersin mix proportion of emulsified asphalt cement mortar suitable for different temperaturezones had been proposed.The achivements of this paper are useful to determine the reasonable mix proportion ofemulsified asphalt cement mortar in practical projects, and are crucial to further improvementof the toughness of emulsified asphalt cement mortar and increasing in the crack resistance ofemulsified asphalt cement mortar and prolonging service life of the ballastless tracks structure.