Study On Properties Of Cement Emulsified Asphalt Concrete

In the southwest, many large-scale hydraulic projects with world-class technical difficulties have being in construction. The proportion of earth-rockfill dam is the largest in these projects, which are with deep overburden layer and deep anti-seepage wall suffering great stress. Meanwhile, a large amount of hazardous reservoirs need to be repaired and reinforced for their anti-seepage wall with high strength and impermeability concrete. In this case, the compressive strength of the commonly used concrete for anti-seepage wall is insufficient for these superior large-scale hydraulic projects, which just satisfy the application needs in temporary cofferdam or permanent hydraulic project with low dam and shallow overburden layer. To solve this problem, it is necessary to explore a kind of moderate-strength, low-elastic module and high-durability cement emulsified asphalt concrete.The properties of cement emulsified asphalt concrete with the different water-binder ratioer, emulsified single-asphalt admixture, single-clay admixture and composite admixtures were investigated in this present paper; The real-time scanning observation on damage crack evolution discipline in cement emulsified asphalt concrete is carried out by means of computerized tomography (CT). By means of Scanning Electron Microscopy (SEM), X-ray diffraction analysis (XRD), and Different Thermal Analysis (TG-DTA) analysis on cement paste micro-structure of cement emulsified asphalt concrete with different mix proportions。From the stuy results, with the increase in water-binder ratio, the emulsified asphalt and clay of the cement emulsified asphalt concrete compressive strength, splitting compressive strength and extreme tensile strength were decreased. the early strength of Cement emulsified asphalt concrete is lower than commom concrete. However, it is fast in late shrength. Mixed with emulsified asphalt and clay, cement emulsified asphalt concrete with a certain plastic, low elastic modulus less than500, even some less than200, but poor-frost resistance and excellent impermeability.Full-section and real-time CT scanning of cement emulsified asphalt concrete indicated that the concrete resilient in compression process. Each section strengthens phase of micro-enlargement and compaction just before ultimate load, whereas after the ultimate load the development of concrete from damage to destroy preceeds stably. Binary image and differentiate analysis further indicated that each section of the crack-formation crack-development different when concrete was under load to failure, and the naked eye is difficult to observe the tiny pores and some initiation but not the development of visible tiny cracks, their existence and development damage the specimen seriously.For cement emulsified asphalt concrete, cement didn’t reacted with emulsified asphalt and no new mineral phase was created. The hydration process of cement asphalt binders mainly presented as cement hydration reaction and cement hydration products formed the hardened paste structural frame.