Cement Emulsified Asphalt Mortar Composition And Properties Of Dry Material

Cement and emulsified asphalt mortar (CA mortar), which consists of cement, emulsified asphalt, sand, water and other admixtures, is one of the key materials of the slab ballastless track structure. In order to improve the efficiency of construction and the quality of CA mortar, cement, sand and other solid admixtures are mixed to the mixtures for CA mortar. At the construction site, the mixtures are mixed with the emulsified asphalt and water, forming the fresh CA motar for the CA motar layer in the slab ballastless track structure. Thus, the performance and quality of the mixtures have a significant effect on the performance, quality and durability of CA mortar layer. Now, the studies on the mixtures are little.In this article, the effects of the size distribution, fineness modulus and maximum size of sand particle in the mixtures on the fresh CA mortar, and the expansive components (aluminium powder and U-shaped expansive agent) and curing conditions on the expansion properties of CA mortar were investigated. Also, the production process and its technological parameter of the mixtures were determined; the effective measure to control the quality of the mixtures was discussed. Finally, the deterioration mechanism of the mixtures during storage was analysed.The main conclusions are summarized as follows:(1) The fineness modulus of sand particles in the mixtures is the main factor influencing the flowability of the fresh CA mortars, but when sand fineness modulus is the same, the size distribution of sand particles has no obvious effect on the flowability of fresh C A mortars. The fineness modulus and maximum size of sand particles are the main reasons influencing the uniformity of CA mortar.(2) The early-age expansion ratio of CA mortar is increased with an increase in the content of aluminium power and a decrease in particle size of aluminium power. The higher curing temperature is, the rapider early-age expansion of CA mortar becomes, and the higher expansion ratio is. Later-age expansion ratio is increased with an increase in the content of U-shaped expansive agent. The later-age expansion ratio of CA motar is not susceptible to the curing humidity.(3) It is the best process for manufacturing the mixtures for CA motar that cement, expansion agent, other admixtures and sand are added in turn to be mixed in the mixer. The pre-dispersion technology used can significantly raise the dispersion of aluminium powder in the mixtures.(4) As the storage age of the mixtures is increased, the expansion ratio and uniformity of CA mortar will be changed due to the deterioration of the mixtures. The deterioration mechanism of the mixtures is that the reaction between mineral components of cement and aluminium powder and the moisture in the air can be occurred during storage.