Compressive strength is the most important mechanical index of ultra-high performance fiber-reinforced concrete (UHPFRC). The rule changes in compressive early-aged UHPFRC great significance to guide curing, formwork removal, and prestress stretching. Therefore, it very necessary study an accurate mathematical model describe change at early age. For this purpose, a new age proposed work for pre...

Abstract Foamed lightweight soil has been widely used in civil engineering, and the model for foam concrete employed to predict its strength. However, various previous strength models of are generally based on assumption complete hydration, which is not case foamed soil. For example, Nambiar’s (reference), a simple model, sets ratio hydrated water cement by weight as an empirical constant, actu...

in this work, a thermoplastic polyurethane elastomer (tpue) model based on polytetramethylene glycol, toluene diisocyanate and 1,4-butanediol was selected and synthesized. according to this model two types of polyurethane nanocomposites were prepared by in situ polymerization and melt intercalation procedures. the organo-modified nanoclay was used in nanocomposites samples in 0.4 weight percent...

the protonation of different species of glycylisoleucine were studied in the ph range of 1.5 - 10 at25 °c using potentiometric technique. investigations were performed in sodium perchlorate andtetraethylammonium iodide as background electrolytes at i (0.1, 0.2, 0.3, 0.4, 0.5, and 0.6) moldm-3. the parameters based on the protonation constants were calculated, and their dependenceson ionic stren...

objectives: mineral trioxide aggregate (mta) is extensively used in endodontics. however, mta is difficult to handle because of its granular consistency, low mechanical properties and initial looseness. the objective of this study was to assess the compressive strength (cs), diametral tensile strength (dts), and ph of set mta using methyl cellulose as liquid. materials and methods: white proroo...

The corrosion fatigue performance of high-strength bolt was studied. Based on the fracture mechanics theory and the Gerberich-Chen formula, the high-strength bolt corrosion fracture crack model and the fatigue life model were established. The high-strength bolt crack depth and the fatigue life under corrosion environment were quantitatively analyzed. The factors affecting high-strength bolt cor...