Evaluation of the strength performance and microstructural properties of different based metakaolin blended cements containing greenly synthesized nanosilica

Abstract

The drive towards improving the properties of cement composite thus making it eco-friendly, sustainable, and durable, has been the focus of the construction industry. Kaolin is one of the pozzolans that have been investigated in recent times, but its reactivity is influenced by its source. In addition, the problem of homogenous mixing onsite and early strength development of pozzolana blended cement are evident. This research focused on the strength and microstructural properties of factory-produced metakaolin blended cement incorporated with green nanosilica. Kaolin samples were obtained from three locations and calcinated at 700 ℃ for 1 h. Metakaolin was interground with 10% Portland Limestone Cement (PLC) clinker at the factory. Binder-sand ratio (1:3) with a water-binder ratio of 0.5 was adopted for batching the mortar. Nanosilica was added to the mortar at: 1, 2, 3, 4, and 5%, respectively. Prisms of 40 × 40 × 160 mm were cast and cured for 3, 7, 14, 28, 56, 90, 180, 270, and 365 days, respectively. The flexural and compressive strengths of prisms including the water absorption of cubes were evaluated. 10% MK addition enhanced the mechanical properties of the mortar with MK C having the highest enhancement. Incorporation of 1% nanosilica enhanced strengths at early and later ages, as well as refinement in the pores of the mortar with increasing nanosilica.