PSI - Issue 66

Sneha et al. / Procedia Structural Integrity 66 (2024) 419–425 Author name / Structural Integrity Procedia 00 (2025) 000–000

421

3

DIC LOP

Digital image correlation Limit of proportionality

MOR Modulus of rapture

2. Experimental Program 2.1. Material and Mix Proportion

To achieve high strength and enhance the packing density in UHPFRC composites, fine-grained reactive material has been used. The requirement for cementitious content is very high in UHPFRC, therefor it has been replaced with other supplementary cementitious material, silica fume and ground granulated blast furnace slag (GGBFS). This will ensure the dense particle packing without compensating the compressive strength. The mix proportions of UHPFRC are shown in Table 1. The UHPFRC consists of cement, silica fume, GGBFS and sand. The high-range polycarboxylic ether bases superplasticizer has been utilized to improve the workability of the mix. The steel fibre of length 20 mm has been used to arrive at the mix design. 2.2. Mix Procedure and Sample Preparation The dry components, including cement, silica fume, GGBFS, and sand, have been initially premixed to ensure a uniform dispersion. Subsequently, water containing the superplasticizer has been gradually added to the dry mixture while continuously mixing. Once the mixture achieved the desired workability, the steel fibres have been carefully added until uniformly dispersed throughout the matrix. To assess compressive strength, cubes of dimensions 150 mm ×150 mm ×150 mm has been cast and tested for 28 days of curing. Additionally, to evaluate fracture properties and examine the influence of fibres on the post-cracking profile, three sets of notched beams have been cast, and the information is given below. The beams, each with dimensions of 700 mm ×150 mm ×80 mm and a notch depth of 30 mm and width of 3 mm, have been consistently used across all three sets. • Set 1: Steel fibre with 2 % fibre volume and fibre length 20 mm. • Set 2: Steel fibre with 2 % fibre with hybrid fibre and length 20 mm (1.5%) and 13 mm (0.5%) • Set 3: Steel fibre with 1.5 % fibre and fibre length 20 mm.

Table 1. Mix proportions of UHPFRC

Mix Composition of UHPFRC

Quantity (Kg/ ) 850

Constituents

Cement

GGBFS

70

Silica Fume

230

Sand

1000

Superplasticizer (SP)

31.05

235.75

Water binder

Steel fibre

157