Modified Emulsified Asphalt On The Sl-1 Mortar Low Temperature Crack Resistance

China railway track systemâ… (CRTSâ… ) is the main type of track structure in Chinese High-speed Railway. Cement and emulsified asphalt mortar (SL-1 mortar) cushion layer which has functions of bracing,adjusting and buffering is the key material of CRTSâ… . Therefore, the performances of SL-1 mortar cushion layer will directly affect the durability of track structure and the security of trains. When SL-1 mortar used in the intense cold area, the insufficiency of the crack-resistance of SL-1 mortar appears, and even it is a threat to the safety of the whole track structure. Until now, few research has been carried out on this problem in china, consequently, it is quite necessary to find a efficient method to improve the crack-resistance of SL-1 mortar at a low temperature.The influence that the ratio of asphalt to inorganic binder materials (A/B), SBS modified asphalt emulsion and some kind of emulsified asphalt modifier, such as SBR emulsion, P emulsion and CR emulsion have on the crack resistance of SL-1 mortar at a low temperature was studied, and also on the working performance, basic mechanical properties, crack-resistance at a normal temperature, basic mechanical properties and crack-resistance at a low temperature of pure Cement and emulsified asphalt paste and SL-1 mortar. The effect law, improvement and mechanism that A/B and emulsified asphalt modifiers have on the performance (mainly crack-resistance at a low temperature) of SL-1 mortar were analyzed.Results show that, ratio of asphalt to inorganic binder materials (A/B), SBS modified asphalt emulsion, SBR emulsion, P emulsion and CR emulsion have effect on performances of pure Cement and emulsified asphalt paste and SL-1 mortar, and mechanical properties of pure Cement and emulsified asphalt paste and SL-1 mortar at a low temperature are quite different from that at a normal temperature. The main difference is that the strength and brittleness increasing, and the crack-resistance reducing when at a low temperature. At the same time, increasing the ratio of asphalt to inorganic binder materials (A/B), choosing SBS modified asphalt emulsion and adding proper emulsions, such as SBR and CR into emulsified asphalt, can improve the performance of crack-resistance of SL-1 mortar at a normal temperature; and choosing SBS modified asphalt emulsion, adding proper emulsions, such as SBR and CR can improve the crack-resistance of SL-1 mortar at a low temperature. It is because polymer can modify some properties of asphalt and its low vitrified temperature makes the Asphalt phase behave good elasticity and toughness that the performance of the crack-resistance of cement-emulsified asphalt mortar can be increased at a low temperature.After experiment analyzing, the mix proportions of SL-1 mortar for intense cold area was fixed:The workability, mechanical properties of SL-1 mortar with the asphalt to inorganic binder materials (A/B) of 0.85, SBS modified asphalt emulsion of 3% by weight and the SBR or CR emulsion 5% by weight can meet the technical requirements, the performance of crack-resistance can also be improved at a low temperature.