White Cement Research Articles

On the capillary water absorption of cement-lime mortars containing phase change materials: Experiments and simulations

Nowadays, the use of phase change materials (PCMs) represents a novel technique employed for retrofitting facades in existing buildings, mainly to fulfil temperature comfort and building energy efficiency requirements. The present study summarizes the results of a wide series of permeability tests carried out for understanding the moisture transport phenomena by capillary action in microencapsulated-PCM (MPCM) porous cementitious composites. Particularly, twelve MPCM cement-lime mortars are analyzed, which were cast with white cement, air lime, siliceous and lightweight aggregates (LWAs), short cellulose fibers and microencapsulated paraffin waxes. A total amount of 10% and 20% of MPCM by volume was added to the plain mixtures, and physical, mechanical and thermal properties of the composites were characterized. The experimental results are employed in an inverse identification procedure aimed at unveiling the key features of the capillary action in these partly saturated MPCM porous systems. A nonlinear FEM-based model for moisture transport phenomena is used with this purpose by adopting an extended Darcy’s law. The capillary pressure is considered to control the overall diffusion-driven mechanism. The outcome of the inverse calibration allows to better understand the influence of each material component (and specially focusing on the MPCM volume fraction) on the resulting diffusion parameters, capillary pressure and the Raleigh-Ritz pore size distribution of the analyzed porous cementitious composites. The inverse calibration procedure showed that MPCM mortars with high values of the Raleigh-Ritz (B) parameter exhibit a low capillary permeability performance. Particularly, it was observed that when MPCMs are added into the analyzed mortars, an increment of the B value is numerically obtained and a subsequent reduction of the permeability performance of the composites is obtained.

Mechanical Characterization of a New Architectural Concrete with Glass-Recycled Aggregate

Concrete is a material which is widely used in architecture, not only for structural purposes but also for architectural elements for its versatility and excellent performance. However, the manufacturing of this material as a mixture of water, cement, and fine and coarse aggregate comes with a high environmental cost, such as gas emissions, among other things. This is the reason why different alternatives are being proposed in order to replace coarse aggregates with other recycled materials, as it is one of the less sustainable components of the mixture in terms of extraction. One of these alternatives is recycled glass coming from drinking bottles, crushed into small grains and mixed in the same proportions as regular aggregates. This study proposes the mechanical characterization of a new architectural concrete mixture by using white Lafarge cement and glass-recycled aggregates; this proposed concrete is made especially for architectural elements like façade panels, rather than structural elements. The mechanical evaluation of this new material is done through a set of experimental tests under compression and also bending, comparing three different ratios of glass aggregate in the mixture.

Dark, heat-reflective, anti-ice rain and superhydrophobic cement concrete surfaces

Antifouling, weatherable, and heat-reflective coatings have much value for solar sheltering of building in summer. In this work, a multifunctional cement mortar mixture was obtained by mixing “cool cold” black pigments with cement, sand, TiO2 nanoparticles and water. After the mixture was mortared on a cement concrete slab, dried at room temperature and treated with fluorine silicon sol, a gray cement concrete layer was obtained. UV–visible-infrared spectrometer confirmed that the layer has obvious infrared-reflective property at 780–2500 nm. Under the radiation of a 275 W and 40 cm height infrared lamp, the surface temperature of the gray “cool cold” cement concrete is about 40 °C lower than that of the carbon black cement concrete, and is about 20 °C lower than that of the ordinary cement concrete, and is only about 1 °C higher than that of the white TiO2 cement concrete. Moreover, all these cement concrete surfaces showed typical superhydrophobic (SH) property and the “cool cold” cement concrete surface further exhibited stable SH properties to both rain and UV radiation, which may allow for self-cleaning performance for the surface and the ability to retain its heat-reflective property over a long period of time. Meanwhile, the “cool cold” cement concrete SH surface exhibited excellent anti-ice rain performance. Because the layer can be easily mortared on the cement concrete substrate, we think it would have great potential for use on building roof and outside walls to reduce air-conditioning energy consumption in the summer.

CONVERSION OF SPENT FAT OIL INTO LIQUID AND GASEOUS FUELS THROUGH CLINKER CATALYZED PYROLYSIS

Abstract Repeated heating of fat oil may result in the formation of highly toxic aldehyde compounds. The oils having such compounds are considered as health hazards and therefore their repeated use is banned in many countries. Since huge quantities of the used oil need urgent disposal, this work is focused on the disposal of used oil for the resource recovery. The waste fat oil was converted into useful fuel through catalytic and non-catalytic pyrolysis. The catalyst was used to lower the oxygen content and to increase the amount of the hydrocarbons in the oil product. The pyrolysis reaction was catalyzed by three catalysts of the clinker type, namely ordinary Portland cement, white cement and burnt clay/clinker powder. The pyrolysis reactions were performed using a custom-made furnace and stainless steel pyrolyzer. Optimum temperature, time and catalyst quantity were identified for high liquid and gaseous fractions and low solid residue. The oil obtained during each reaction was characterized for chemical composition by using GC-MS technique. The oil product of simple pyrolysis, cement catalyzed, white cement catalyzed and clinker catalyzed pyrolysis had the hydrocarbon contents of 3%, 19%, 51% and 93%, respectively.

Effects of the Applied Pressure and Pressing Speeds on the Total Resistance of the Compressibility Process

The compaction apparatus is used in this study to measure the total resistance of particles during the compressibility process for approaching the real resistance of the particles in the ball mill and to simulate the grinding in an actual ball mill in order to be used for design purposes. The apparatus consists of two punches and a large die which a single punch pressing. The size reduction is measured because it gives an indication to the total resistance and the grinding product of the coarse particles of white cement clinker manufacture by Alkhomes refractory. The effect of the compaction applied pressure and compaction velocity are studied. Results indicated that the high total resistance (Tr) occurred at high compaction speed, low applied pressure and at increase the weight of a compacted material.

Influence of curing temperature on cement paste microstructure measured by 1H NMR relaxometry

1H nuclear magnetic resonance (NMR) relaxometry, supported by X-Ray diffraction and thermogravimetric analysis, has been used to characterise microstructure of white cement pastes underwater cured at temperatures in the range 10 °C to 60 °C. As the temperature increases, so the C-S-H, capillary pore water and interhydrate pore water content all increase; the ettringite and gel pore water content decrease; and the Portlandite content stays constant. A non-linear increase in the C-S-H ‘solid’ and ‘bulk’ densities, that exclude and include gel pore water respectively, has been observed with the increase of temperature. This is accompanied by a decrease in C-S-H water content but no change in the Ca/(Si + Al) ratio. The increase in the C-S-H ‘solid’ density has been attributed to a decrease in the number of locally stacked C-S-H layers. The increase in the C-S-H ‘bulk’ density is additionally attributed to the decrease in the gel porosity.

Production and Application of Aggregate Manganese Zeolite Greensand using Post Cartridge Micron as Absorbent Fe and Mn Ions

The purpose of this study was to produce an aggregate of fine manganese greensand and its applications using micron cartridge design for absorbing Fe3+and Mn2+ ions in the well water affected by the Lapindo mud. The fine manganese greensand was made using the flame spray pyrolysis. The combination of aggregate material and the bulk manganese greensand were performed with the adding filler with the varied compositions of CaO, CaCO3, and white cement as the adhesive. Characterization of topography, morphology, and composition of aggregate manganese greensand was performed using SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-Ray). Applications of the aggregate manganese greensand and activated carbon were designed in several post cartridge microns for well water samples. Initial and final measurement the concentration of Fe and Mn solution using a calibration curve by AAS method (Atomic Absorbance Spectrophotometer). The results showed that the aggregate A with a composition of fine manganese greensand: bulk manganese greensand: CaCO3: CaO and white cement is 2:5:1:1:1:1 and aggregate B (3:4:1:1:1) absorbed maxima ions of Mn (97.5%) and Fe (80.3%) in the well water sample, respectively. Besides, the profile of spectrum SEM-EDAX indicated the aggregate A and B interacting with filler which showed the active situs as exchange cation for absorbing Fe3+ and Mn2+ ions.

Prediction of Bending Strength of Self-Leveling Glass Fiber Reinforced Concrete

Many studies have been conducted on the prediction of fiber reinforced concrete strength; however, there are very rare data concerning the prediction of bending strength values of self-leveling glass fiber reinforced concrete. And there is no study for prediction of bending strength of self-leveling glass fiber reinforced concrete from mixture ingredients and slump values. In the present study, relationships between the bending strength and the mixture proportions are explored. An artificial neural network model (ANN) is designed with an extensive experimental data including 395 four-point bending tests, and input parameters as white cement amount, maximum aggregate size, glass fiber content, water cement ratio, superplasticizer and metakaolin content and slump test results. Effect of each parameter on the bending strength is investigated with the developed model. An empirical and user-friendly formula was obtained with the generalization capabilities of the ANN. Results showed that the prediction results are in good agreement with the field data. And these numerical results with high efficiency can make it possible to use the neural design for real-life self-leveling glass fiber reinforced concrete applications.

Catalytic and noncatalytic conversion of spent fat oil into combustible gases and liquids

A huge amount of spent oils is produced in the world every day. These oils contain some toxic aldehydes, which affect human health. The disposal of used oils in sewers and drains not only raises the blockage and aesthetic problems but also pollutes the water resources. In the present work, spent fat oil (SFO) was converted into a combustible liquid and gaseous fuels by using a batch type reactor. For catalytic pyrolysis, the Portland cement raw mix, white cement raw mix, and powdered nonbrick or clay catalysts were used to convert SFO into useful fuels. The uncatalyzed pyrolysis took 60 min to convert SFO into liquid and gaseous fuels. The pyrolysis time was reduced to 30 min after catalyzing the reaction with a suitable catalyst. The white cement raw mix and clay catalysts promoted the formation of gaseous products, whereas the Portland cement raw mix promoted the formation of liquid fuel. The uncatalyzed pyrolysis of SFO produced only 3.527% hydrocarbons. Among the catalyzed reactions, the highest percentage of hydrocarbons (67.884%) was obtained with clay catalyst followed by the white cement (55.24%) and Portland cement (35.893%) formulations. The uncatalyzed reaction mainly produced fatty acids, the Portland cement and clay/burnt brick catalyzed reactions produced only esters, and the white cement catalyzed reaction produced a single fatty acid.

A Study on NO Removal Efficiency of Titanium Dioxide by Binder and Pigment

The reduction is limited because most of the measures focus on blocking the source through regulation. Therefore, this study is a study on the development of treatment technology using Photocatalytic so as to prevent the conversion of Nitrogen ion causing fine dust into fine dust through secondary generation in order to develop a technology that can remove the causative substance. For the development of the technology, experiments were carried out on the change of NO removal rate to binder type, construction method and pigment. Natural cement and white cement were used as binders. The method of construction was compared with concrete placement and spraying. The removal rates of green, red and black pigments were observed. Experimental results show that the removal rate of natural cement is higher than that of white cement by 56~67%. Experiments on the construction method show that the removal efficiency of the spraying without vibration is more than 2 times higher than that of the concrete placement method. The effect of the pigments on the pigments was found to be lower than that of red and black irrespective of binder and construction method. Key words: Photocatalysis, TiO2, Fine Dust, Removal Rate, Binder, Pigment

Development and testing of grouts based on perlite by-products and lime

Abstract Grouting is a widely used intervention technique for the consolidation and strengthening of historic masonries. During the recent decades, lime-based grouts have been developed, tested and applied, taking into account parameters, such as their compatibility with the historic structures and their performance both in terms of fresh and hardened state properties. The exploitation of perlite by-products on the other hand (named as ‘waste perlite’), is a field that should be further envisaged, due to the gradually increasing demand of expanded perlite production, as well as the need of minimizing the environmental burden from its industrial process. To this direction, a series of grout mixtures based on two types of perlite by-products (D1S and D1C) and lime (air and hydraulic) were manufactured and tested. According to the experimental results, waste perlite-based grouts presented effaceable fresh and hardened state properties, while their performance was enhanced when superplasticizer and a short proportion of white cement or metakaolin was added in the air lime mixtures. In the hydraulic lime mixtures, the addition of waste perlite enhanced their properties and significantly increased their strength. Therefore, it was concluded that according to specific requirements, both perlite by-products studied could be used in combination with lime, for the manufacture of light-weight, low cost and environmental friendly grouts. Future oriented research should be therefore made in order to further investigate the parameters influencing the performance of grouts based on other waste perlite types.

Synthesis of white cement bonded porous fumed silica-based composite for thermal insulation with low thermal conductivity via a facile cast-in-place approach

Abstract High performance thermal insulation material was prepared by fumed silica as thermal insulation matrix, white cement as binder. SiC powder was incorporated as an opacifier. Short glass fibers were added to increase stiffness and minimize contraction. The samples were produced within 4 days under ambient pressure with no complicated equipment. The influences caused by white cement amount on the properties were investigated to achieve the optimal performance. A low thermal conductivity 0.033 W·m−1·K−1 at 25 °C and a low thermal conductivity 0.038 W·m−1·K−1 at 800 °C were achieved based on the experimental results. The linear shrinkage of the insulation up to 800 °C in air for 30 min was 7.54%. In addition, the insulation exhibited a compression stress above 0.15 MPa (3% strain). The relation between structure and performances was revealed. That we here publicly reported thermal insulation materials synthetized by nano-powder and inorganic binder might reveal a new method for synthesis high performance thermal insulation materials. Based on the simplicity of the manufacturing process, the optimized material properties and cheap cost of raw materials, we believe this technology can act as an effective thermal insulation material for buildings and myriad applications requiring improved thermal efficiency.

Enhancement of Some Mechanical Properties of White Cement Mortar by Adding Nanoparticles of Zirconium Oxide

This paper will study mortar compressive strength (fc) and flexural strength (fr) by cement replacement which is partial with the particles of Nano-Zr2O3. Zr2O3nanoparticles are used as well as using average diameter of 35 nm with four various contents by weight of cement (0.25%, 0.75%, 1.25% and 1.75%). The (fc) and (fr) tests were performed after the process of curing at the 28-days which is the standard age. The preparation of mortar of Nano-cement was done by using the ratio of cement-sand by weight which is 1:3 with the ratio of water-binder materials (w/b ratio) as 0.5. The results demonstrated that the (fc) and (fr) of the mortars of cement with Zr2O3were registered higher than cement mortar that is pure. The ultimate Nano-cement mortar strength was obtained at 1.25% of the replacement of cement. The improvement in (fc) and (fr) were 15.6 % and 18.4% in a respective way at 28 days.

Enhancement of Some Mechanical Properties of White Cement Mortar by Adding Nanoparticles of Zirconium Oxide

This paper will study mortar compressive strength (fc) and flexural strength (fr) by cement replacement which is partial with the particles of Nano-Zr2O3. Zr2O3nanoparticles are used as well as using average diameter of 35 nm with four various contents by weight of cement (0.25%, 0.75%, 1.25% and 1.75%). The (fc) and (fr) tests were performed after the process of curing at the 28-days which is the standard age. The preparation of mortar of Nano-cement was done by using the ratio of cement-sand by weight which is 1:3 with the ratio of water-binder materials (w/b ratio) as 0.5. The results demonstrated that the (fc) and (fr) of the mortars of cement with Zr2O3were registered higher than cement mortar that is pure. The ultimate Nano-cement mortar strength was obtained at 1.25% of the replacement of cement. The improvement in (fc) and (fr) were 15.6 % and 18.4% in a respective way at 28 days.

Enhancement of photocatalytic activity of self-cleaning cement

The present study involves the use of activated dolomite to enhance the photoactivity of self-cleaning cement containing microsized-TiO2. Two kinds of self-cleaning cement samples with different composition of clinker (white cement), activated dolomite and microsized-TiO2 were prepared in-house. The prepared cement samples and ingredients were characterized by XRD (X-ray diffraction) patterns, SEM (scanning electron microscopy), BET (Brunauer-Emmett-Teller) analysis and EDS (energy dispersive X-ray spectroscopy). Photocatalytic activity test was performed to evaluate the self-cleaning abilities of the prepared cement samples. The photocatalytic activity test was also repeated for three times to confirm the reusability of the cement samples for commercial and field applications.

Radiological characterization of building materials used in Malaysia and assessment of external and internal doses

In this study, the activity concentrations of 226Ra, 232Th, 222Rn, and 40K, emanation fractions (P), equilibrium equivalent concentration (EEC), and mass exhalation rates (Em) of radon released from building materials used in Malaysia were studied using gamma-ray spectrometer with HPGe detector. Radiological parameters [activity concentration index (ACI), indoor air-absorbed dose rate (Din), annual effective dose (AEDin) from external and internal (ERn), soft tissues (HST) and lung (HL), and effective dose equivalent (Heff)] were estimated to evaluate radiological hazards due to the use of these building materials: sand, cement, gravel, bricks, tiles, fly ash, white cement, and ceramic raw materials. The measured P, EEC, and Em vary from 10 to 30%, 0.9 to 22 Bq m−3, and 33 to 674 mBq h−1 kg−1, respectively, while the calculated ACI and AEDin vary from 0.1 ± 0.01 to 2.1 ± 0.1 and 0.1 ± 0.01 to 2.4 ± 0.6 mSv y−1, respectively. On the other hand, the internal annual effective dose ranges from 0.1 to 1.4 mSv y−1. The estimated radiological risk parameters were below the recommended maximum values, and radiological hazards associated with building materials under investigation are therefore negligible.

Albedo Estimation of Finite-Sized Concrete Specimens

Abstract Albedo in the context of the Urban Heat Island contributes to the environmental impact of a pavement. Measuring the pavement albedo is difficult as it depends on the size of the specimen, background interference, and variations in the incoming solar spectrum. For this study, the albedo was determined for a 1-m2 concrete slab cast with white cement containing titanium dioxide nanoparticles. The size of the exposed surface of the slab was varied using black paper. To calculate the albedo of these nonstandard specimen sizes, a new testing technique was proposed that uses an albedometer and various geometric conditions, including the exposed slab surface and measurement height. The albedo of the finite-sized concrete specimen was found to range from 0.50 to 0.55, depending on the number of unknowns assumed, with the most reasonable estimate of 0.54. The measured slab albedo from the new method was also verified using a laboratory spectrophotometer. With this proposed methodology to account for background surfaces, the albedo of laboratory-sized concrete specimens of any shape can now be easily measured at various test site locations.

Nano Titania combined with micro silica reinforced limestone cement:Physico-mechanical Investigation

The influence of different ratios of fillers addition such as limestone and micro white sand, as well as nano-titania particles on the physico-mechanical properties of ordinary white Portland limestone cement (OWPC), has been studied. One mix (10.00 wt. %) of equal ratios from limestone and white sand in micro scale, partially replaced by cement clinker. Mechanical strength, phase composition, and microstructure of blended cement have been investigated. The results showed that filler reduces the setting time and total porosity, improve the strength, free lime content, combined water content and bulk density of cement pastes due to the pozzolanic effect of micro white sand that replaces clinker and enhance an excess amount of hydration products. It can be concluded that limestone fills the pores between cement particles due to the formation of carboaluminate, while micro sand increases the hydration C-S-H product. TiO2 nanoparticles (i.e., less than 100 nm) shows a great efficiency in enhancing the mechanical strength of cement paste due to the incorporation efficiency of nanoparticles as active sites for gel Tobermorite C-S-H fibers growth during hydration,

Microwave Curing Effect on Internal Sulphate Damage in Nano Alumina Reinforced White Cement

In this study, microstructural investigation was carried out to analyse the internal sulphate damage in the nano-Al2O3 (nAl) reinforced white cement pastes. As white cement is generally used in the production of architectural concrete, 52.5 R type white cement was preferred in the scope of the study. Nano Al2O3 was substituted into the cement paste at 0% and 5% ratios. Three different methods were used for microwave curing. Different microwave curing techniques were performed as 120 minutes of 100 Watt application, 75 minutes of 100 Watt-30 minutes of 150 Watt-15 minutes of 200 Watt application, and 90 minutes of 100 Watt-15 minutes of 150 Watt-15 minutes of 200 Watt. In order to accelerate the formation of DEF damage, Na2SO4 was added to the cement paste at 2%, and 5% ratios. Three different microwave curing methods were used to investigate the occurrence of DEF damage in nano Al2O3 reinforced concrete concretes. In the pastes produced for this purpose, dense ettringite structure was observed. In cement pastes without nAl, the ettringite structure had a low S / Ca ratio (<0.20). More ettringite was formed in methods 2 and 3 used as microwave curing. The heat treatment applied in the microwave curing was the same as in other thermal curing applications, and in case the inner sulphate source was present it led to the formation of ettringite. This process became more evident in the presence of NA by increasing power application

Efficient Spent Sulfidic Caustic (SSC) Wastewater Treatment Using Nano TiO₂-Bottom Ash (NTB) Composite.

Novel composites with nano-sized TiO₂ synthesized on the surface of bottom ash (NTB) were prepared for treatment of spent sulfidic caustic (SSC) wastewater. The efficiency of SSC wastewater treatment was compared and evaluated by using NTBs made with organic binder and inorganic binder, respectively. The treatment efficiency of NTB composite made with organic binder was higher than that of NTB composite made with inorganic binder. Although NBT composite made with inorganic binder had many pores on the surface, the white cement used as binder was excessively applied to the surface, and amount of coated nano-sized TiO₂ was decreased. The photocatalytic activity of nano-sized TiO₂ is more effective for SSC wastewater treatment than surface adsorption ability of surface pores.