Characterization of the grout produced from argillaceous limestone for the consolidation of historic buildings

Abstract

In this study, firstly, natural hydraulic lime was produced by calcining an argillaceous limestone containing 70% calcium carbonate at 950 degrees C and 1100 degrees C. The sample calcined at 1100 degrees C was subjected to mechanical grinding since it was found suitable for injection grout production according to its mineralogical and chemical composition and its cementation and hydraulic index values obtained by XRD and XRF analyses. Grain sizes of the ground sample and a common commercial grout material were determined by DLS analysis. The comparison following XRF and DLS analyses revealed that the ground sample has smaller grains in the nanometer range and higher cementation and hydraulic index values than the commercial product. Various grouts were prepared with the addition of water and chemical admixture to the ground sample in different ratios. Fluidity, volume stability and penetration properties of the grouts were evaluated according to Marsh Funnel, Flow Cone, bleeding, and sand column tests, respectively. The limit requirements of these tests were achieved with the selected water to binder ratio, chemical admixture amount and mixing procedure. Moreover, bending and compression tests were performed on the hardened grouts on the 28th and 90th days. The grout prepared with selected proportions and mixing procedure showed higher flexural and compressive strength on the 90th day than the commercial one. Based on these results, it has been concluded that the new grout can be an alternative to existing commercial products used for the consolidation of historic buildings.