The tensile strength of cement paste was increased by 56% and the modulus and ductility were increased by 39% by using silane-treated carbon fibers and silane-treated silica fume, relative to the values for cement paste with as-received carbon fibers and as-received silica fume. Silane treatment of fibers and silica fume contributed about equally to the strengthening. Silane treatment of fibers...

Compatibility between sulfonated acetoneformalehyde superplasticizer (SAF) and copolymer-based grinding aids (GA) were studied by fluidity, Zeta potential, setting time of cement pasts, initial slump and slump flow of concrete and compressive strength of concrete. ESEM, MIP, and XRD were used to investigate the changing of microstructure of interior concrete. The results indicated that GA could...

polymeric yarns for reinforcing cement composites have got great interest in all over the world. in this research the performance of bonding between nylon tire cord grad yarns, and one kind of cement composite called fine grained concrete was studied. two kinds of nylon cord yarns, nylon 6 and 66, with different finesse were selected. the durability of yarns with time in alkaline media was inve...

In the twenty-first century, most high-performance concretes, and many other ordinary concretes, are now based on blended cements that contain silica fume, slag, and/or fly ash additions. Because the chemical shrinkage accompanying the pozzolanic and hydraulic reactions of these mineral admixtures is generally much greater than that accompanying conventional portland cement hydration, these ble...

Electrode effects on impedance spectra of cement pastes were investigated by two-, three-, and four-point measurements without a potentiostat over the frequency range 0,01 Hz–10 MHz. Electrode immittance effects arising from highly resistive/capacitive contacts cannot be fully corrected by nulling procedures, Two-point~measurements are much more susceptible to such effects than threeor four-poi...

Cement manufacture has undergone extensive change in its attempts to rise to the successive challenges posed by society. The hydration of Portland cement is a complex phenomenon that depends on both reagent characteristics and reaction conditions. It is a well-known fact that the curing temperature plays an important role on the hydration kinetics. The present study is the first to be undertake...

Cement-based materials, especially those with low water-cement ratios, often experience premature cracking due to plastic shrinkage in the early curing stages. In this study, development mechanism of early-age cement paste, and crack control effect recycled paste powder on was quantitatively investigated using non-contacting two-dimensional digital image technology. The influence different repl...

H nuclear magnetic resonance (NMR), supported by a measurement of the degree of hydration using X-ray diffraction, has been used to fully characterise the nano-scale porosity and composition of calcium-silicate-hydrate (C-S-H), the active component of cement. The resultant “solid” density and composition are 3 g/cm 68 . 2 = ρ ; (Ca)1.53. (Si0.96,Al0.04)O3.51.(H2O)1.92 for an underwater cured, n...

Assuring the quality of the massive quantities of cement produced worldwide each year is a daunting task. Currently, the cement industry performs extensive physical testing to assess the quality of their product, resulting in large costs for both materials (and their disposal) and labor. One of the major goals of the Virtual Cement and Concrete Testing Laboratory (VCCTL) consortium is to provid...

A mathematical model is established for chloride penetration in saturated concrete. The model takes into account various influential parameters such as water-to-cement ratio, curing time, types of cement, and aggregate content. Two material models are developed for binding capacity and chloride diffusivity, which have a dominant effect on the chloride diffusion process. The chloride binding cap...