International Journal of Civil, Environmental and Agricultural Engineering

Experimental Evaluation of Sisal-Fibre-Reinforced Concrete Utility Blocks Containing Crushed Ceramic Tile as Fine Aggregate

2026-08-05T04:40:21+00:00

This experimental study evaluates concrete utility blocks incorporating crushed ceramic tile as a partial replacement for fine aggregate and alkali-treated sisal fibre as reinforcement. Crushed tile replaced fine aggregate at 10%, 20%, 30%, and 40% by mass. After identifying the best-performing tile replacement, sisal fibre was added at 1.0%, 1.5%, and 2.0% by mass of cement. Workability was assessed by the slump test, and compressive strength was measured after 7, 14, and 21 days of water curing. Slump decreased from 130 mm for the control mixture to 45 mm at 40% tile replacement and decreased further with increasing fibre content, confirming reduced workability. Among the tile-modified mixtures, the 30% replacement mixture produced the highest compressive strengths of 27.476, 30.298, and 31.156 MPa at 7, 14, and 21 days, respectively. When sisal fibre was incorporated into the 30% tile mixture, the 1.5% fibre dosage provided the highest reported strengths of 35.560, 41.223, and 44.184 MPa. A further increase to 2.0% fibre reduced strength, indicating an optimum within the investigated range. The findings support the technical feasibility of combining crushed ceramic fines and treated sisal fibre in non-structural concrete utility blocks. However, the study is limited to workability and compressive strength; durability, water absorption, dimensional stability, tensile performance, and full-scale paving-block compliance require additional testing before practical deployment.

Experimental Investigation of Bacteria-Based Self-Healing Concrete through Microbially Induced Calcium Carbonate Precipitation

2026-08-05T04:41:08+00:00

Cracking accelerates the ingress of water and aggressive species into concrete and consequently reduces the durability of civil infrastructure. This experimental study evaluates a bacteria-based self-healing concrete containing Bacillus subtilis and calcium lactate as a nutrient source. Three mixtures were considered: a control mixture without bacteria (M1), concrete containing 10⁵ cells/mL (M2), and concrete containing 10⁷ cells/mL (M3). Compressive strength was measured after 7, 14, and 28 days. Crack closure was monitored for an initial crack width of 0.50 mm, and water absorption was evaluated for the control and highest-concentration mixtures. At 28 days, M2 and M3 achieved compressive strengths of 34.7 and 35.8 MPa, respectively, compared with 32.5 MPa for M1. The corresponding increases were 6.8% and 10.2%. After 28 days of healing exposure, the crack width decreased to 0.05 mm in M3, corresponding to 90% apparent crack closure, whereas the control crack decreased only to 0.45 mm. Water absorption decreased from a reported control value interpreted as 5.02% to 3.8% for M3. These results indicate that the higher bacterial concentration improved compressive strength, reduced water absorption, and promoted crack sealing under the reported laboratory conditions. The findings remain preliminary because replicate numbers, variability, mineralogical confirmation, permeability measurements, and long-term durability data were not supplied.

Preliminary Isolation and Phenotypic Characterization of Bacillus-Like Bacteria from Marine Coastal Soil

2026-08-05T04:41:31+00:00

Marine environments constitute an underexplored source of microorganisms with potential applications in food, aquaculture, and biotechnology. This study aimed to isolate cultivable bacteria from coastal soil collected at Kanyakumari Beach, Tamil Nadu, India, and to perform preliminary phenotypic characterization. Three sample types—dry surface soil, wet soil, and soil collected between rocks—were serially diluted and cultured on solid bacterial medium. Representative colonies from each sample were purified and evaluated for colony morphology, Gram reaction, cellular morphology, arrangement, and motility. More than 80 colonies were observed from each sample type. Three representative isolates, designated D, W, and R, formed medium-sized whitish colonies with predominantly circular morphology. All isolates were Gram-positive, rod-shaped, and motile; cells occurred singly or in short chains. These characteristics support their provisional classification as Bacillus-like bacteria. However, phenotypic observations alone are insufficient for species-level identification or for establishing probiotic functionality. Molecular identification, safety testing, and functional assays—including acid and bile tolerance, antimicrobial activity, adhesion-related properties, antibiotic susceptibility, and haemolysis—are required before any probiotic claim can be made. The present work therefore provides a preliminary culture collection and a foundation for subsequent strain-level evaluation.

Muskmelon Peel Extract-Reinforced Chitosan/Gelatin/Starch Composite Films for Biodegradable Food-Packaging Applications

2026-08-05T04:39:46+00:00

Petroleum-derived food-packaging materials provide useful mechanical and barrier performance but create persistent end-of-life waste. This study reports the preparation of biodegradable composite films based on chitosan, gelatin, starch, glycerol and muskmelon peel extract (MPE). Chitosan was obtained from mud-crab shell waste through deproteinisation, demineralisation, decolourisation and deacetylation. Muskmelon peel was dried, milled and extracted using an aqueous ethanol system. Composite film-forming solutions containing 0%, 10% and 30% MPE were prepared by solution casting. Fourier-transform infrared spectroscopy was used to examine the functional groups of the extracted chitosan, and macroscopic film formation was assessed after drying and conditioning. The extracted material exhibited the characteristic broad hydroxyl/amino absorption region and amide-associated bands expected for chitosan. Continuous self-supporting films were obtained at the tested MPE concentrations, with visible formulation-dependent differences in colour and appearance. These observations demonstrate the feasibility of incorporating muskmelon peel-derived components into a chitosan/gelatin/starch matrix. However, tensile strength, elongation, water-vapour permeability, antioxidant capacity, antimicrobial activity, migration safety, biodegradation and food shelf-life performance were not quantitatively evaluated in the present work. The films should therefore be considered preliminary laboratory prototypes rather than validated food-contact packaging. Future studies should establish composition-property relationships and verify safety and preservation performance using standardised methods.