Characterization of Cementitiously Stabilized Layers for Use in Pavement Design and Analysis

Abstract

Bottom-up cracking may be due to CSL surface raveling or fatigue of the CSL, as follows:(a) Bottom-up cracking due to CSL surface raveling Based on accelerated pavement testing, studies show that the surface of a stabilized base layer can ravel, creating a layer of loose material between the HMA and base CSL (Figure A-8). Raveling of the base increases the strain level at the bottom of the HMA, which can result in alligator cracking. In addition, pumping was observed in these cases. The pumping is caused by the loss of fines in the loose material layer. This phenomenon may be linked to the erodibility of stabilized materials, which often happens when relatively fine raw materials are treated (De Beer 1985). reported the loose layer is about 0.8 in. thick and is believed to be due to shear failure within the CSL as a result of horizontal loading, which in turn causes alligator cracking.

Strength and Stiffness Studies of Cement Stabilized Granular Lateritic Soil

“…9. It may be observed that the flexural modulus and MOR increases with increase in UCS which is in consistent with the earlier studies (Wen et al 2014;Arulrajah et al 2015;Austroads 2008). Figure 10 shows a comparison between predicted flexural modulus and measured flexural modulus of CLS after 28 days curing periods.…”

“…It may be observed that, the modulus increases with stress ratio. This behavior of CLS is in line with gravel-cement, silt-cement and clay-lime (Wen et al 2014). As already mentioned, flexural modulus at a stress ratio of 0.4 have been taken as the modulus of that sample as per the study of Austroads (2008).…”

“…Although elastic modulus of cemented materials can be estimated by monotonic compression test, third point flexure test is better for determination of modulus due to the similarity in development of stress-strain gradient generated in a pavement (Wen et al 2014;Austroads 2008;Arulrajah et al 2015;Yeo et al 2011). Laboratory determination of stiffness or modulus values of cement stabilized materials depends on the type of test.…”

“…The beam specimen have been subjected to haversine cyclic load of 100 cycles having a peak load which is equal to 20%, 30% and 40% of failure load of beam samples determined from flexure test. Modulus value corresponding to 40% of failure load have been taken for determination of flexural modulus (Wen et al 2014;Yeo et al 2008). …”

“…4 (present study), Eq. 5 (Wen et al 2014) respectively. The default value of MOR of soil cement adopted by IRC 37: 2012 and MEPDG for fatigue analysis is 0.7 MPa for UCS value of 5.17 MPa is very conservative for CLS as the predicted MOR obtained from Eq.…”