Experimental investigation on partial cement replacement with binary blended bagasse ash and calcined dolomite for enhanced C-25 grade concrete performance

Abstract

Cement is a globally produced building material and a crucial component of every construction project. Alternative materials, mostly agro-industrial wastes, are emerging as potential cement replacements due to high carbon dioxide emissions associated with cement manufacturing and rising cost of cement. Numerous naturally occurring materials like rice husk ash, corn cob ash, fly ash, slag, silica fume, bagasse ash (BA), and natural pozzolans are used as partial substituents for cement in concrete and mortars due to their strength, cost-effectiveness, and environmental benefits. BA is frequently used as a partial cement replacement in concrete, but most studies limit its utilization to 15%, highlighting the limitations of pozzolanic materials. This study investigates the effects of binary blended BA and calcined dolomite powder (CDP) as partial cement replacement, i.e., 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%, on the compressive strength of C-25 grade concrete. Additionally, the physicochemical properties of BA, CDP, and the binary mixture were studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray fluorescence (XRF), and dynamic light scattering (DLS). Furthermore, the effects of the binary mixture on workability, setting time, compressive strength, strength activity index (SAI), water absorption, and dry density on the concrete were evaluated in detail. The compressive strength was examined by casting 66 standard cubes of 15 cm [Formula: see text] 15 cm [Formula: see text] 15 cm size and curing them for 7 and 28 days. The compressive strength test indicates that by reducing pozzolana particle size below cement grade and blending BA with CDP, up to 30% of cement can be replaced by enhancing the compressive strength to 36.7 MPa at the end of 28 days.

Keywords: Bagasse ash; C-25 grade concrete; Calcined dolomite; Compressive strength; Partial replacement; Pazzolona.

Fig. 1

Gradation graph of (a) fine and (b) coarse aggregates.

Fig. 2

Sample preparation of bagasse ash.

Fig. 3

Calcination of dolomite powder at 925 °C.

Fig. 4

DLS analysis of (a) bagasse ash, (b) calcined dolomite powder and (c) mixture of BA and CDP.

Fig. 5

XRD analysis of (a) bagasse ash, (b) calcined dolomite, (c) mixture of BA,CDP andOPC.

Fig. 6

FTIR analysis of (a) bagasse ash (b) calcined dolomite powder (c) mixture of BA, CDP and OPC.

Fig. 7

Secondary electron SEM image of (a) bagasse’s ash, (b) calcined dolomite powder, (c) binary mixture of BA and CDP (d) mixture of BA, CDP and OPC.

Fig. 8

Slump value as the percent of BA and CDP increase.

Fig. 9

(a) The Vicat needle test method (b) initial and final setting times for the mix.

Fig. 10

The 7th and 28th days compressive strength value for a partial replacement of OPC with 5% increment of (BA + CDP).

Fig. 11

7th and 28th days strength activity index.