Journal of Materials Science Research, Issue: Vol.15, No.1

Effect of Selected Cement Brands on the Service Life of Reinforced Concrete

Wed, 01 Apr 2026 14:02:00 +0000

The paper investigates the differences in the chemical composition of the selected Cem 1 cement brands in Kenya and their effect on mechanical properties of concrete. It also investigates if the differentiation in mechanical properties of concrete prepared from different cement brands affects its service life. Currently, there are nine cement manufacturers in Kenya, the majority of whom produce Cem 1 cement along with other grades. To achieve the desired objective, three cement brands; Cem A, Cem B and Cem C of Cem 1 were used in preparation of concrete samples for testing. Other concrete constituent materials; fine and coarse aggregates and steel were obtained from the local Kenyan market suppliers. The physical and chemical properties of the materials were investigated to ensure compliance with relevant applicable standards. Concrete of characteristic strength of 25N/mm2 derived from the DOE method was used. Concrete materials were batched by weight and mixed by a lab electric pan concrete mixer in batches of 0.009 m3 . The concrete batches were tested for consistency by the slump and compaction factor tests. For each brand of cement 9 cubes of 150mmx 150mm x 150mm for compression test, 9 cylinders of 150mm x 300mm for tensile strength were cast. After 24 hours the cast specimens were demolded and immersed in curing tanks for 27 days. Specimens for compression and tensile test were tested at 7,14 and 28 days. From the results in the research, the different Kenyan selected cement brands affect the compressive strength which influences the rate of infiltration of corrosion agents affecting the service life of reinforced concrete. The variation in chemical composition must be taken into account when formulating the concrete mix design for specific structural purposes.

Physicochemical and Mineralogical Characteristics of Geopolymer Formulated from Kaolinitic Clay

lamine_zerbo@yahoo.fr (Lamine ZERBO) — Tue, 12 May 2026 08:03:21 +0000

Canola meal as a by-product from the vegetable oil production provides a protein-rich material which is available This study investigated the potential of Burkina Faso’s local kaolin clay in formulation of geopolymer bricks. The formulation used a mixture of raw clay and activator alkaline solutions with varying concentrations. Prismatic molds were used to shape geopolymerized adobes. The physicochemical characteristics of the samples, including water absorption, linear shrinkage, density, porosity and spray test, were determined after 28 days. According to the standard NF P 15-471 mechanical analyses revealed that the geopolymer, formulated from locally sourced clay and a (NaOH + sand) solution with 10M concentration, exhibited favorable performance characteristics essential for civil engineering construction. These include a maximum linear shrinkage of 5.31%, a density ranging from 1.607 g.cm-3 to 1.900 g.cm-3, porosity of 29.90%, acceptable mass loss following a rain erosion test of 0.56%, and excellent compressive strength of 28 MPa. Mineralogical characterization results demonstrated that all formulated bricks contain quartz, kaolinite, goethite and a novel phase Na2(AlSiO4)6(OH)2.2H2O.

Sol–Gel Spin-Coated Multilayer nc-Si Thin Films on Silicon Substrates: Controlled Growth, Composition, and Electronic Structure

Tue, 12 May 2026 08:02:37 +0000

Silicon multilayer thin films consisting of alternating amorphous SiOx (a-SiOx) and nanocrystalline silicon (nc-Si) layers were fabricated on p-type silicon substrates using a sol-gel spin-coating method. Boron-doped silicon powders, prepared through prolonged grinding, were mixed with a TEOS–ethanol sol-gel solution, and two nc-Si layers embedded in a-SiOx were sequentially deposited. The as-grown films were annealed at 100–400 °C and characterized using Raman spectroscopy, GXRD, FTIR, SEM, Resistivity and UV spectroscopy to analyze their structural, chemical, optical, and electronic properties. Annealing progressively enhanced crystallinity and increased the <111> and <110> grain sizes to ~11 nm and ~12 nm, respectively. Films annealed at higher temperatures showed a minimum mobility of ~37.5 cm²/V·s, maximum resistivity of ~7.35 Ω-cm, and a decreasing optical bandgap. Enhanced nanocrystal growth, reduced defects, and improved structural ordering intensified the 520 cm⁻¹ Raman peak. The multilayer architecture further strengthened these effects by offering additional nucleation sites, controlled nanocrystal confinement, defect-relaxing interfaces, improved phonon transport, and enhanced Si diffusion, resulting in superior crystalline quality.