PSI - Issue 71

Dharmadas Bairagi et al. / Procedia Structural Integrity 71 (2025) 417–423

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2. Experimental Investigation 2.1. Materials

Lime (Conforming to IS 712: 1984) is collected from AB brick plant, Nagpur. PoP (Conforming to IS 1288:1982) were sourced from local commercial vendor. Soil collected from farmland in Bankura a district of west Bengal. It is of Old alluvial soil type having mass thickness 1.42 gm/cc, percentage sand content 54.7%, percentage earth 20.3%, and percentage silt 25%. Test were performed on soil and found to be conforming to IS 2720: 2020. Waste Bamboo chips were collected from Maharashtra Bamboo Development Board. Bamboo waste is generally of two types of viz. flacks and fibres. The collected material is in the form of flakes. It was pulverised and sieved to 3 mm to receive bamboo fines . Crushed bamboo fines have bulk density of 2.56. Coconut coir was sourced from waste coconut shells from local market. The fibers were separated from shells and desired size of coir fibre was extracted out with help of pulveriser. The coir fibre below 60 mm is used in this experiment. For bamboo mesh, matured bamboo were collected, bamboo culms were split vertically, then inner and outer nodes were removed. Then the outer green bark was removed and the individual strips having average thickness of 1.5 mm were extracted for bamboo mesh. A square mesh of 300 mm width with strips at a spacing of 20 mm is made. The raw materials have been shown in figure 1.

Lime Sample

PoP

Soil Sample

Bamboo fines

Coir Fiber

Bamboo Mesh

Figure1: Raw Material used in study

2.2. Sample Preparation and Testing In the present study Square panels of 300 mm width and 25 mm thickness were casted using Hydraulic Press Machine. A Square M S mould of 300mm with 45 mm depth was fabricated using two L shapes with a detachable lower plate (figure 2a) A lower M.S plate was used for easy extraction from the mould. During casting a 20 mm thick plywood sheet was used as upper plate for pressing the material into the mould to achieve 25 mm panel thickness. Material was manually mixed and consistency was checked using ball test. Water was added accordingly to achieve a cohesive ball of mix. Casting is done under a maximum pressure of 75 kg/cm 2 . Panels were air dried under shed for 24 hours and after that sun dried for 48 hours. A surface treatment with paper sheets on both side by fixed with commercially available PVA glue is done on panels. In all the samples were casted for three compositions (1) Binder-Bamboo Filler (BB) (2) Binder-Bamboo Filler Coir fiber (BBC), and (3) Binder-Bamboo Filler-Bamboo mesh (BBM) (figure 2b-2c). In the binder, lime and PoP together are termed as lime binder, and are mixed in a ratio of 3:1. For fixing optimum ratio of lime binder to soil, 70.6 mm cube sample were casted and 3-day compressive strength was checked. The proportion of lime binder to soil was varied as, 20:80, 50:50, 80:20 and 100:0. Composition showing maximum strength was selected as matrix composition for further sample preparation. To decide the optimum percentage of bamboo fines as filler, 70.6 mm cube samples were casted varying the percentage of bamboo fines as 10%, 16%, 22%, 28%, 34%, 40% of dry weight of binder. The samples were designated by B10 to B38. Water to dry mix ratio was initially taken as 0.55 and adjusted for ball consistency. Three specimens were casted of each composition and 3-days compressive strength was conducted. Panels were casted using the bamboo fines 22-38% with an interval of 2% to total dry weight of binder. It was observed that these panels show poor handling strength irrespective of percentage of bamboo fines. Thus, reinforcement was introduced in mix. Panel samples with continuous reinforcement (Bamboo mesh of 20 mm spacing) designated as “BBM” and discrete reinforcement (coconut coir fiber 20 gm) “BBC” earlier were casted.