THE EFFECT OF LIME AND CEMENT IN FOAM BITUMEN MIXES

摘要

The application of foam bitumen to aggregates and preparation of foam bitumen mixes have significant advantages in terms of environmental conservation. Traffic disruption and time delays will be limited if foam bitumen is applied in the form of in-place processing. Foam bitumen mixes that are produced in cold mix operations refer to bituminous mixes containing aggregates and foam bitumen. The behavior of foam bitumen treated materials depends on the proportion of the mix, the type of aggregates, bitumen and the active fillers used. In this work, foam bitumen mixes containing cement and/or lime (as active fillers) have been prepared using a laboratory foam-bitumen producing unit. Mixes containing no active fillers were prepared and their optimum binder contents were determined. The effects of adding lime, cement and lime-cement slurries were then analyzed. Among all the parameters that affect the mix, the water content was considered to be the most influential variable. Mechanical properties of the prepared foam-bitumen mixes were evaluated using Marshall and Indirect Tensile Strength (ITS) tests. The ITS test was performed on samples at both dry and soaked conditions to control their moisture susceptibility and their durability. Marshall Quotient (the ratio of stability to flow) was also so that to control the rigidity of mixes. It was noted that the aggregates had excessive water absorption. Upon adding a few percent of the above active fillers, the strength values of the samples were increased appreciably. It was also noted that adding small quantities of cement and/or lime makes the mixes quite rigid (with cement stiffening the most). The optimum results were achieved when a combination of lime-cement slurry was added to the mix.