China
Africa
Explore chapters and articles related to this topic
Lime, cement and concrete
Published in Arthur Lyons, Materials for Architects and Builders, 2019
White Portland cement is manufactured from materials virtually free of iron oxide and other impurities, which impart the grey colour to Portland cement. Generally, china clay and limestone are used, and the kiln is fired with natural gas or oil rather than pulverised coal. Iron-free mills are used for the grinding process to prevent colour contamination. Because of the specialist manufacturing processes, it is approximately twice the price of the equivalent grey product. To further enhance the whiteness, up to 5% of white titanium oxide pigment may be added. The standard product is to strength class 52.5N. Typical applications include renderings, cast stone, precast and in situ structural concrete and pointing.
Composition and properties of Portland cements
Published in Anjan Kumar Chatterjee, Cement Production Technology, 2018
The C4AF phase imparts gray colour to cement and white cement, therefore, has a restricted presence of Fe2O3 below 0.4%. For a higher whiteness index, some manufacturing units maintain their own raw materials specifications, limiting all the coloring oxides like Cr2O3, NiO, V2O5, etc. A special quenching system forms a critical part of the manufacturing process. Oil or gas instead of coal is used as the fuel. Needless to mention that white Portland cement is used for decorative cementitious products including concrete.
SBR-latex modified cementitious composite coatings for concrete rehabilitation and assessment of performance measure
Published in European Journal of Environmental and Civil Engineering, 2022
Ketankumar G. Chitte, Ravindra G. Puri, Dhiraj S. Mahajan, Sachin Rathi, Jitendra S. Narkhede
Malvern (mastersizer 3000) particle size analyzer was used to analyze particle size distributions of various types of cement used in the preparation of coatings. Cement hydration is initiated when it comes in contact with a humid environment forming hydrates that might change the virgin size of cement particles. To avoid this, a simple dry dispersion technique was used to estimate particle size distribution and the specific surface area of White Portland Cement (WPC), Ordinary Portland Cement (OPC) and Pozzolonic Portland Cement (PPC). Cement particles were pushed under vacuum and passed through the laser beam where the scattering of light was detected by photodetectors. Signals received from photodetector were converted to particle size distribution data using a Mastersizer preprogrammed software interface where Mie scattering or Fraunhofer diffraction model was used. The particle refractive index of 1.68 was kept constant for all samples considering that the laser diffraction is not a standard test to determine the fineness of cement particles.
Study on the use of lightweight expanded perlite and vermiculite aggregates in blended cement mortars
Published in European Journal of Environmental and Civil Engineering, 2022
Tzer Sheng Tie, Kim Hung Mo, U. Johnson Alengaram, Senthil Kumar Kaliyavaradhan, Tung-Chai Ling
White Portland cement was used for all mixes in this study. GGBS and fly ash were used as partial cement replacement. The chemical compositions of GGBS and fly ash were evaluated by X-ray fluorescence (XRF) spectrometry analysis and presented in Table 1. Mining sand was used as fine aggregates while two different types of lightweight aggregates (EV and EP) were incorporated as the sand replacement. The physical properties of GGBS, fly ash, EV, EP and sand are summarised in Table 2. The particle sizes of GGBS and fly ash were determined by particle size distribution (PSD) analysis whereas the particle sizes of sand, EV and EP were obtained by sieve analysis based on BS EN 933-1: 2002 and presented in Figure 1. The specific gravity and water absorption of sand, EV and EP were determined through pycnometer test based on BS EN 1097-6: 2013 and given in Table 2. The mixing water used was from pipe water in the laboratory.
NMR T1–T2 correlation analysis of molecular absorption inside a hardened cement paste containing silanised silica fume
Published in Molecular Physics, 2018
Calin Cadar, Andrea Cretu, Marioara Moldovan, Carlos Mattea, Siegfried Stapf, Ioan Ardelean
In this work, the influence of the silanised silica fume addition on the pore size of inter-C–S–H (calcium silicate hydrate) [4] and capillary pores of the hardened cement paste, will be studied. Two samples will be considered, both prepared with white Portland cement, with or without the addition of silanised silica fume. The silanisation of silica fume will be performed using APTES (3-Aminopropyltriethoxysilane). For 2D NMR relaxometry investigations, the samples will be saturated with water or ethanol. The DSC thermoporometry measurements on hardened cement pastes saturated with OMCTS (Octamethylcyclotetrasiloxane) will provide information about the pore size.