Abstract
Limestone dust (LSD) from stone quarries is promising as a partial cement replacement for the production of ecofriendly self-compacting concrete (SCC). Proper collection and utilization of dust from stone crushers in aggregate quarries will contribute to resolving longstanding environmental issues in several countries. In this study, LSD from stone quarries was collected from various sources and suppliers. The suitability of LSD for resolving longstanding environmental issues was investigated in the production of ecofriendly SCC mixes. Physicochemical analyses of LSD samples revealed significant variations between sources but only limited variations among shipments from the same source. SCC mixes with LSD from certain sources and shipments exhibited significant degradation in the workability retention, compressive strength, and pinhole formation. However, these undesired effects attributed to minor constituents and clayey-like materials can be mitigated by modest adjustment of PCE dosage. Image analysis technique has enabled an interpretable representation of pinhole formation and distribution in SCC mixes in connection with the effect of LSD source. A methylene blue value (MBV) test was used to confirm the presence of clayey-like materials in LSD samples. From this test, it can be concluded that LSD samples have a probable clay contamination content of less than 1% as compared to the LSD samples with 1% natural bentonite. Good correlations between both MBVs and V-funnel flow time as well as pinholes surface area could be established. Three effective practical approaches are shown to relatively overcome the pinhole formation in SCC mixes.