Incorporation of Cement Bypass Dust in Hydraulic Road Binder

Abstract

This article describes utilization of a cement kiln bypass dust utilization as an added component in a hydraulic road binder. Three experimental binder mixes (BM1–BM3) with variation in the composition of the main constituents (cement clinker, ground limestone and ground granulated blast furnace slag) and constant content of bypass dust (10%) were prepared under laboratory conditions. The properties of binder constituents, fresh experimental binder mixes and hardened specimens were tested according to STN EN 13282-2 for a normal hardening hydraulic road binder. The physical and chemical properties of all binder mixes (fineness: +90 µm ≤ 15 wt.%; SO3 content: <4 wt.%) met the standard requirements. The bypass dust addition led to an increase in the water content for standard consistency of cement mixes (w/c = 0.23) and to a shortening of the initial setting time for two experimental blended cement pastes (BM1 and BM3) compared with the value required by the standard. Only BM2 with the lowest SO3 content (0.363 wt.%) and the highest percentage of granulated blast furnace slag (9.5 wt.%) and alkalis (Na2O and K2O content of 5.9 wt.%) in the binder mix met the standard value for the initial setting time (≥150 min). The results of compressive strength testing of experimental specimens after 56 days of hardening (59.2–63.9 MPa) indicate higher values than the upper limit of the standard requirement for the N4 class (≥32.5; ≤52.5 MPa).

Optimization of an Eco-Friendly Hydraulic Road Binders Comprising Clayey Dam Sediments and Ground Granulated Blast-Furnace Slag

“…Therefore, the sulfate contents for both mixes are well below the EN 13282-2 standard value of 4%, which is required for normal hardening hydraulic road binders. These results agree with those obtained by Stevulova et al (2021) [25].…”

“…For example, the residue by mass at 90 µm reduction for the mixes 50C35GGBS15CS and 80C10GGBS 10CS were 50% and 20% than that of the control, respectively. These results agree with those reported by Stevulova et al (2021) [25]. The mixes in this study satisfied the EN 13282-2 condition for normal hardening hydraulic road binder because their percentages of residue by mass at 90 µm were less than 15%.…”

“…The three mixes are qualified as plastic even after 90 min because their flow values are higher than the threshold limit of 140 mm [41]. The cement substitution by the supplementary materials can lead to a workability decrease as reported in previous studies [4,25]. However, the workability decrease remains negligible.…”

“…In fact, the finer the material is, the higher its specific area and water demand. The workability of fresh mortar is controlled by several factors, such as fineness, water to binder ratio, shape of particles, and hydration rate [25,40]. Figure 7 shows an angular shape for SCM.…”

“…Few studies have been carried out on adding supplementary cementitious material to prepare hydraulic road binders. Stevulova et al (2021) [25] studied the incorporation of granulated blast furnace slag, ground limestone, and cement bypass dust to produce a normal hardening hydraulic road binder. Segui et al (2013) [5] evaluated the effect of natural pozzolan on the stabilization of a clayey soil as a main component of the produced hydraulic road binder.…”