Experimental Investigation

Experimental investigation was carried out through selection and testing of materials, determination of concrete mixture proportions, and preparation and testing of various fresh concretes.

Materials

Ordinary (ASTM Type I or CSA Type 10) portland cement, crushed granite stone, pit sand, non­crystalline amorphous rice husk ash (RHA), tap water, poly-carboxylic acid-based high-range water reducer (HRWR), and a synthetic air-entraining admixture (AEA) were used to produce various SCC. Crushed granite stone and pit sand were selected as coarse and fine aggregates, respectively, whereas rice husk ash was used as a supplementary cementing material. Prior to use in preparing concrete mixtures, the component materials were tested for a number of physical properties. These properties were useful to judge the suitability of the constituent materials. In addition, most of these properties were directly used in mixture proportioning of different concretes. The physical properties of the concrete materials are given in Table 1.

Table 1: Physical Properties of Constituent Materials

Material

Properties

Crushed granite stone

Maximum size: 19 mm

Total evaporable moisture content: 0.1%

Oven dry basis bulk density: 1670 kg/m3 Void content: 37%

Saturated surface-dry basis relative density: 2.71 Absorption: 1.5%

Fineness modulus: 6.78

Pit sand

Maximum size: 4.75 mm

Total evaporable moisture content: 0.1%

Oven dry basis bulk density: 1860 kg/m3 Void content: 28%

Saturated surface-dry basis relative density: 2.62 Absorption: 1.0%

Fineness modulus: 2.74

Ordinary portland cement

Relative density: 3.16 Blaine fineness: 412 m2/kg

Rice husk ash (RHA)

Relative density: 2.07

Tap water

Density (240C): 997.28 kg/m3

High-range water reducer (HRWR)

Relative density: 1.069 Solid content: 41%

Air-entraining admixture (AEA)

Relative density: 1.01 Solid content: 12.8%