PSI - Issue 70

K. Navin Balaji et al. / Procedia Structural Integrity 70 (2025) 295–302

297

2. Materials And Methodology 2.1 Materials

The research utilized Ordinary Portland Cement 53-grade per IS 12269-2013 standards as the main binding agent. Limestone powder (LSP), extensively utilized as a mineral additive for its filler and nucleation properties, was obtained from Shree Sakthi Minerals in Coimbatore. Rice Husk Ash (RHA), a highly pozzolanic by-product, was procured from a local rice mill after controlled combustion and sifting. Coconut shell aggregates (CSA) were procured, purified, sun-dried, and manually crushed to appropriate size for use as lightweight coarse aggregate. M-sand compliant with Zone II as per IS 383:2016 was employed as fine aggregate. Natural coarse aggregates measuring 12 mm were also employed. A superplasticizer based on polycarboxylate ether (1.2%) was employed to improve the workability of the mixes. All materials were stored in dry, sheltered conditions and utilized in accordance with standard specifications. All mixing and curing operations used potable water with no impurities which met the standards of IS 456-2000. Table 1 presents the key characteristics of cementitious materials and aggregates employed in the study, whereas Fig. 1 depicts the constituents utilised in this study.

Table 1. Properties of Cementitious Materials and aggregates Material Specific Gravity

Fineness (m²/kg)

Fineness Modulus

Water Absorption (%)

Bulk Density (kg/m³)

Cement (OPC)

3.15 2.70 2.10 2.65 1.20 2.70

310 480 560

– – –

– – –

– – –

LSP RHA CSA NSA M-Sand

– – –

2.75 6.40 6.85

1.20 5.85 0.80

1680 710 1650

(c)

(a)

(b)

Fig.1. Sample of materials; (a) LSP; (b) RHA; (c) CSA

Table 2. Mix proportions of all mixes Mix ID Cement

LSP

RHA

M-sand

CSA

NCA Water

SP

(kg/m³)

CC

450

0

0 0

840 840 840 840 840 840 840

0

700 560 560 560 560 560 560

180 180 180 180 180 180 180

5.4 5.4 5.4 5.4 5.4 5.4 5.4

RHA-0 RHA-5 RHA-10 RHA-15 RHA-20 RHA-25

382.5

67.5 67.5 67.5 67.5 67.5 67.5

140 140 140 140 140 140

360

22.5

337.5

45

315

67.5

292.5

90

270

112.5

2.2 Methodology A mix design for M30 grade SCC followed both IS 10262:2019 and EFNARC- 2005 guidelines. The control mix (CC) consisted entirely of OPC with no substitution of materials. The test series employed LSP as a continuous cement replacement of 15% while gradually increasing RHA percentages from 0 to 25% in 5% increments to determine its