Experimental study of bitumen emulsion–cement mortars: mechanical behaviour and relation to mixtures

Abstract

Cold bitumen emulsion mixtures are ecofriendly materials for road pavement construction. Portland cement and other supplementary cementitious materials are added to the mixtures to improve their performance. In bitumen emulsion-cement (BEC) mixtures, the two binders affect the mechanical behaviour and the curing process. In this research, BEC mixtures are considered as multiphase composite materials consisting of a mortar matrix and coarse aggregate inclusions. The main objectives are to identify the composition of BEC mortar phase and to compare mixtures and mortars throughout the curing process. Starting from two BEC mixtures containing 80% reclaimed asphalt, eighteen mortars were manufactured by changing their water and air voids content. Then, two design composition were selected to analyse the curing process by monitoring indirect tensile strength (ITS), indirect tensile stiffness modulus (ITSM) and moisture loss. Results showed that the short-term ITS of mortars (1 day of curing) increased by reducing their water and their air voids content. During curing (from 1 to 28 days), the mechanical properties (ITS and ITSM) of mixtures and mortars increased in a similar way. Unique relationships were identified between mortar and mixture properties, regardless of bitumen to cement (B/C) ratio, curing time and curing condition. In terms of predictive behaviour, the design composition slightly underestimated mixture stiffness and overestimated mixture strength. Keywords Cold paving technologies Á Bitumen emulsion Á Cement Á Mortar Á Curing The original version of this article was revised due to a retrospective Open Access order.

Use of fine aggregate matrix to analyze the rheological behavior of cold recycled materials

“…In the field of cold bituminous materials, which clearly includes CRM mixtures, mortars were considered either as model systems for investigating the properties of bitumen emulsions and their interaction with the cementitious binders [28,29] or, alternatively, to investigate the properties of the CRM mixture itself [30].…”

Comparing the Field and Laboratory Curing Behaviour of Cold Recycled Asphalt Mixtures for Binder Courses

“…Figure 10 shows the evolution of the average ITSM values over the curing time for gyratory specimens (Group 0) and core specimens of Group 2. The experimental data were fitted through the asymptotic model proposed by Graziani et al [ 23 , 58 ]: where t (days) is the curing time, y ( t ) is the property under investigation (ITSM), t i is the curing time when the property was measured for the first time (i.e., 3 or 73 days), y i is an intercept term that represents the value of the properties at the time t i , y a is the long-term asymptotic value of y ( t ) and h y (days) is a parameter representing a specific curing time. The parameter y i gives information on the average rate of evolution of the material properties from the day of construction to t i .…”

“…Figure 10 shows the evolution of the average ITSM values over the curing time for gyratory specimens (Group 0) and core specimens of Group 2. The experimental data were fitted through the asymptotic model proposed by Graziani et al [23,58]:…”

Mechanical behaviour of bitumen emulsion-cement composites across the structural transition of the co-binder system

“…This perspective is analogous to the model systems of bitumen-filler mastic used in conventional bituminous materials [30,31,32], however, with much higher degree of complexity, as the intrinsic mechanical properties of these two co-binders are radically different. In this regard, bitumen is a viscoelastic rheodictic material characterised by time and temperature-dependent mechanical behaviour.…”