نتایج جستجو برای: cement paste
تعداد نتایج: 35130 فیلتر نتایج به سال:
in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...
Multiscale modeling for cement-based materials, such as concrete, is a relatively young subject, but there are already a number of different approaches to study different aspects of these classical materials. In this paper, the parameter-passing multiscale modeling scheme is established and applied to address the multiscale modeling problem for the integrated system of cement paste, mortar, and...
The results of oneand two-dimensional H nuclear magnetic resonance (NMR) pulsed field gradient (PFG) diffusometry studies of water in white cement paste with a water-tocement ratio 0.4 and aged from 1 day to 1 year are reported. The study shows that the NMRPFG method is primarily sensitive to the capillary porosity. Data is fit on the basis of a lognormal pore size distribution with pore size d...
The integrated disposal of surface subsidence pits and surface solid waste can be realized by backfilling a surface subsidence area with a paste made from the solid wastes of mines, such as tailings and waste rock. The microstructures of these wastes determine the macroscopic properties of a paste backfill. This paper presents an experimental study on the internal structure evolution of pasty f...
We report the first nuclear magnetic resonance (NMR) two-dimensional correlation T(1) - T(2) and T(2) - T(2) measurements of hydrating cement pastes. A small but distinct cross peak in the two-dimensional relaxation spectrum provides the first direct evidence of chemical exchange of water between gel and capillary pores occurring over the first 14 days of hydration. A correlation of features al...
Co-extrasion involves extrasion of multiple layers at the same time. Functionally graded materials comprising various layers with different properties can be produced through co-extrusion. Rheological control is vital for successful co-extrusion of layered cement-based materials. The paste flow in the barrel and the die land in a ram extruder should be plug-like, while the paste should be shear...
This study aimed to investigate the processing parameters and biocompatibility of a novel biphasic dicalcium silicate (C₂S) cement. Biphasic α´L + β-C₂Sss was synthesized by solid-state processing, and was used as a raw material to prepare the cement. In vitro bioactivity and biocompatibility studies were assessed by soaking the cement samples in simulated body fluid (SBF) and human adipose ste...
Concrete is the second most used material worldwide and the first used man-made material. Its production entails large emissions of GHG due to lime decarbonation during the clinkering process, as well as large consumption of non-renewable minerals and natural aggregates. Currently legislative pressure aiming at preserving natural resources is growing tighter on natural aggregates extraction, wh...
In this work, graphene nanoplatelets (GNPs) were dispersed uniformly in aqueous solution using methylcellulose (MC) as a dispersing agent via ultrasonic processing. Homogenous GNP suspensions were incorporated into the cement matrix to investigate the effect of GNPs on the mechanical behavior of cement paste. The optimum concentration ratio of GNPs to MC was confirmed as 1:7 by ultraviolet visi...
Cement is one of the mostly used construction materials due to its high durability and low cost, but it suffers from brittle fracture and facile crack initiation. This article describes the use of naturally-derived renewable cellulose nanofibers (CNFs) to reinforce cement. The effects of CNFs on the mechanical properties, degree of hydration (DOH), and microstructure of cement pastes have been ...
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