Cement Technology Research Articles

Design and application of well cementing technology based on the precise managed pressure balancing method in narrow pressure window hole sections

In the Sichuan Basin, the drilling of complex deep and ultradeep wells is restricted by the casing sequence. Multiple pressure systems are usually encountered in the same open hole section, and narrow safety density window is observed in vertical strata. The application of managed pressure drilling (MPD) technique which is often used in well drilling ensures the safe and efficient drilling, but it also brings about great challenges to the small-gap liner cementing at the lower part. Therefore, it is of great practical significance to research a cementing technology that can not only satisfy the quality requirement of small gap liner cementing, but also ensure the safe cementing in the strata with narrow safety density window. In this paper, a cementing technology based on precise managed pressure balancing method was proposed by referring to the successful application of MPD technique. According to the cementing design, the hydrostatic column pressure of annulus fluid is under-balanced (slightly lower than the formation pore pressure), and then a precise managed pressure drilling device is adopted to produce back pressure through wellhead restriction or apply wellhead compensation pressure, so that the balanced pore pressure can be reached in the process of cementing via the wellhead pressure and the flow friction of fluid in the annulus. After the cementing is completed, a certain compensation pressure is applied to the annulus continuously to prevent annulus channeling during waiting on cement caused by insufficient static pressure and slurry weight loss. After this technology was applied to an ultradeep exploration well in the Sichuan Basin, the qualification rate of borehole cementing quality reached 97%, and the well sections with good cementing quality accounted for 76%. In conclusion, this technology needs no additional equipment, and only by virtue of the MPD equipment, it can achieve safe cementing construction and cementing quality improvement under high displacement efficiency.

Lafarge, Solidia ramp up low-CO₂ concrete

LafargeHolcim and Solidia are extending a partnership to commercialize low-carbon dioxide technology for cement and concrete in the US and Europe. The two firms joined in 2013 to advance Solidia’s ...

Synergistic effect of a small amount of silica aerogel powder and scrap rubber addition on properties of alkali-activated slag mortars

The combined use of smart and waste – based materials for energy efficiency in buildings seems as a promising solution. Due to its unmatched insulation properties, silica aerogel is an attractive smart material in cement technology compared to other conventional insulation materials. However, the high manufacturing cost of silica aerogel limits its application in the construction industry. In this study, the combined effect of silica aerogel (0%, 0.3% and 0.6% of binder weight) and scrap rubber (0%, 1.5% and 3.0% of binder weight) addition in alkali-activated slag (AAS) mortars was investigated. A small amount of silica aerogel and scrap rubber addition into mixtures was analyzed with the aim of minimizing reductions in mechanical properties with enhanced thermal insulation. Experimental results demonstrated that in the case of 3.0% scrap rubber loading at 0.3% aerogel content ratio, a remarkable synergistic effect could be observed in terms of thermal insulation up to 33%. Besides, after 2 days of curing, 48.35% and 77.55% increases in compressive toughness and post – peak compressive toughness of samples were detected, respectively. Synergistic effect of a small amount of silica aerogel and scrap rubber in calcium-silicate structure indicates a great potential for energy conservation.

An Effect of the Epoxy Cementing Technology on the Deformation of the Optical External Surfaces Made of Quartz Glass

The problematic issues, associated with deformations of the outer surfaces of optical parts made of quartz glass, due to the process of cementing, are considered. The effect of the heat treatment temperature of optical assemblies, consisting of parts made of quartz glass and cementing with epoxy cements OK-72FT5 and OK-72FT15, on the deformation of external surfaces was experimentally established. The object of the study was plane-convex and plane-concave lenses made of quartz glass. It has been stated, that on cementing with optical epoxy cements OK72FT5 and OK72FT15 the external quartz glass surface deformations depend primarily on the heat treatment temperature. When cementing parts are made of quartz glass, increasing the polymerization temperature improves the performance characteristics of products and reduces changes in their optical characteristics.

Hot corrosion behaviour of Al-Si-Dy coating on new γ′-strengthened cobalt-based alloy

Dy-Si-modified aluminide coating was deposited onto new γ′-strengthened cobalt-based superalloy by pack cementation technology. The coating is composed of an outer layer and a diffusion zone in thickness of around 70 μm and 11 μm, respectively. The outer layer consists mainly of AlCo containing Al5Co2 dispersoids. The weight gain of Al-Si-Dy coating after hot corrosion at 1173 K for 100 h is 0.36 mg/cm2. Al-Si-Dy coating shows better corrosion resistance by contrast with Al and Al-Si coating. The hot corrosion mechanisms of Al-Si-Dy coating is discussed in this study.

To the Question of Structure Formation of Dispersed Systems in Cement Technology

In the this publication, readers will find the results of the analytical and experimental research into the physical and chemical processes in the consecutive formation of structures at the major technological stages of the present-day production of portland cement. Dispersed systems of raw mixtures, which in different methods of production are formed at the stage of grinding, mixing and homogenization of raw materials, belong to different classification groups. In wet and combined methods is produced cement sludge - aqueous dispersed system, which belongs to the 2nd group: two-phase systems such as solid dispersed phase - liquid dispersion medium. In the dry method dispersed system is formed, which belongs to the 3rd group: three-phase systems such as solid dispersed phase - water-liquid and air-gas dispersion medium. The structural-mechanical and rheological properties of the coagulation structure of cement slurries, wich differ in the main raw material components, are shown. The study of deformation processes of aqueous dispersed systems showed that the nature of the development of deformations - rapid elastic ε₀’, slow elastic ε₂’ and plastic ε₁’τ sludge samples belong to different structural - mechanical types. At the same time differences in quantitative values and a ratio of the specified types of deformation are noted. Readers will also find the particularities of the phase changes in the process of the crystallization structure formation at baking to maximum temperature 1450°С.

Correction to: Cementing Technology of Salt-Paste Bed

To the article “Cementing Technology of Salt-Paste Bed,” by Lanbo Xu Feng Qian, Xiangji Kong, Jiming Yuan, and Xiaoming Wu, Vol. 55, No. 4, pp. 457-462, September, 2019

Development of Cement Technology from Heisei to Reiwa

Development of Cement Technology from Heisei to Reiwa

Numerical simulation and reliability verification of pulverized coal combustion in rotary kiln and decomposing furnace under O 2 /CO 2 condition

In order to study the feasibility of reducing CO2 and NOx emission by using O2/CO2 flue gas cycling calcinating cement technology, a numerical simulation method was used to study the pulverized coal combustion of the 2 500 t·d−1 rotary kiln and decomposing furnace models under 21%O2/79%CO2 combustion-supporting atmosphere. The simulations results of rotary kiln and decomposition furnace under O2/CO2 combustion-supporting conditions and air-supported combustion conditions were compared and analyzed. The reliability of numerical simulations was also verified by experiments test. The results showed that in comparison with the air-supported combustion conditions, the pulverized coal burnout rate of the rotary kiln and decomposing furnace under O2/CO2 combustion-supporting conditions were 92.41% and 91.15%, respectively, which decreased by 3.06% and 3.51%. The decomposition rate of raw materials at the exit of the decomposing furnace was 90.54%, which decreased by 2.90% and still basically met the production demand. Under O2/CO2 combustion-supporting conditions, NO emission of rotary kiln and decomposing furnace decreased significantly, and the denitrification rates were 74.47% and 11.80%, respectively. The CO2 volume fraction in flue gas increased from 32.23% to 95.35%, and the C capture could be achieved through simple treatment. This study provides a reference for the generalization and application of the O2/CO2 flue gas cycle calcinating cement technology.

Effect of waste glass powder addition on properties of alkali-activated silica fume mortars

In cement technology, sustainable-based politics demands the use of industrial by-products and waste – based materials. Glass powder (GP) and silica fume (SF) are excellent solid materials to develop a sustainable cement-based material due to a high content of silicon dioxide (SiO2) in their chemical compositions. This study focuses on the properties of alkali-activated silica fume (AASF) mortars containing waste glass powder (WGP). For this purpose, WGP was utilized as partial replacement of sand in AASF mortar mixtures at four levels: 0%, 15%, 30%, and 45% by weight. Displacement -controlled compressive and flexural strength tests were carried out on prismatic 40 × 40 × 160 mm test samples that had been cured for 2,7 and 28 days. The Mercury Intrusion Porosimetry (MIP) test and the thermal conductivity coefficient measurement were carried out following the compressive strength test on 28-day samples. The microstructure morphology and mineralogical properties of the mortar samples were studied by means of Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), respectively. Experimental studies have shown that at a replacement level of 30%, WGP simultaneously improves the flexural strength of mortars by 12.65% and reduces the thermal conductivity coefficient by 30.88% under stable macro pores and transient capillary–micro pores formation in AASF pore structure. As an alternative to conventional cement mortar, WGP-incorporated AASF mortars attract a great deal of attention.

Research on Technology of Drilling in High Temperature and High Pressure Gas Field in South China Sea

The HTHP (high temperature and high pressure) areas of the Ying-qiong Basin in south China Sea has the characteristics of high temperature, high pressure, many pressure steps and narrow safety density window. The severe geological conditions pose a serious challenge to safe drilling in HTHP environment. Through more than 20 years of technical research and field practice. A set of key drilling technologies suitable for HTHP areas in south China Sea have been formed, including: multi-genesis formation pressure prediction, HTHP drilling fluid system, safe cementing technology, ECD accurate prediction technology, and drilling speed increasing technology. The engineering practice of safe drilling in the HTHP area of the South China Sea improves the efficiency of operation and ensures safe drilling. At the same time, the key technology also provides guidance for offshore drilling in HTHP areas.

TiO2-based Photocatalytic Cementitious Composites: Materials, Properties, Influential Parameters, and Assessment Techniques.

Applications of heterogeneous photocatalytic processes based on semiconductor particles in cement-based materials have received great attention in recent years to enhance the aesthetic durability of buildings and reducing global environmental pollution. Amongst all, titanium dioxide (TiO2) is the most widely used semiconductor particle in structural materials with photocatalytic activity because of its low cost, chemically stable nature, and absence of toxicity. Utilization of TiO2 in combination with cement-based materials would plunge the concentration of urban pollutants such as NOx. In fact, cementitious composites containing TiO2 have already found applications in self-cleaning buildings, antimicrobial surfaces, and air-purifying structures. This paper aims to present a comprehensive review on TiO2-based photocatalysis cement technology, its practical applications, and research gaps for further progression of cementitious materials with photocatalytic activity.

Consequential life cycle assessment of Brazilian cement industry technology projections for 2050

In the upcoming decades, cement production growth is expected to exceed the increase in availability of clinker substitutes. Increased clinker replacement rates in cement and use of alternatives fuels were pointed out as the main alternatives for reducing emissions of the national cement industry, whilst increasing cement production in 2050. Consequential life cycle assessment (CLCA) offers a framework to capture environmental consequences from demand alterations. Modelling the cement production and markets involved is however challenging, given conceptual (only unconstrained markets are considered) and practical modelling limitations (e.g. model granularity compatible with CLCA interests). This paper refers to an ongoing work and adopts a two-stage approach to discuss the effects of the change on the average cement production process in Brazil. We first performed a CLCA without formal affected market identification to estimate the potential environmental impacts of the technology change proposed in the Brazilian Cement Technology Roadmap. Secondly, we used a Computable General Equilibrium (CGE) Model of the Brazilian economy to (more) realistically foresee short-term effects induced by such change. The CGE model comprises 102 economic activities, including cement production and its production chain. Our results indicate that (i) increasing the proportion of calcined clay and limestone filler as clinker partial substitutes and (ii) excluding charcoal from the fuel mix composition at the kiln would impact all economic sectors. Our preliminary findings suggest that the increased efficiency in cement production would create some rebound effect that would not invalidate the emission benefits from displacing energy and virgin materials. Additional impact categories and consequences in other economic sectors should be further investigated.

Novel technology to reduce risk lost circulation and improve cementing quality using managed pressure cementing for narrow safety pressure window wells in Sichuan Basin

Narrow safety pressure window wells using either conventional cementing technology or positive injection and reverse-squeeze technology often face two problems: lost circulation and a poor cementing quality. Managed pressure cementing (MPC) technology, developed based on managed pressure drilling technology can solve these problems and reduce the risk of lost circulation. In this study, we expounded on the working principles, equipment and operations of MPC technology. We also proposed a calculation model for the wellhead compensatory pressure. MPC technology can increase the displacement from 12.5 to 20.0 L/s and ensure that annulus pressure is within the safe pressure window. Field applications show that MPC technology can reduce the lost circulation and improve the cementing quality. When applying MPC technology, attention should be paid to the control of cement slurry density to ensure that it remains within the design range.

Efflorescence of Alkali-Activated Cements (Geopolymers) and the Impacts on Material Structures: A Critical Analysis

Even with the rapid development of the alkali-activated cement (AAC) technology in the past few years, some phenomena still needs to be better understood, that may alter the durability of the material. In many industrial uses and laboratory researches the formation of the salts on the surface alkali-activated type cements was observed, which was identified as efflorescence. This occurs due to the presence of an alkali transported in contact with the humidity and CO2 environment. It may present externally from the formation of salts on the surface and internally with the carbonation of the alkalis in capillary pores. The effects of efflorescence on the material in use, as well as all factors that can influence its formation are not yet fully understood or reported. The search for papers was conducted using the search words efflorescence and geopolymer/alkali-activated, combined in the electronic data base. Due to the limited quantity of papers published related to efflorescence in geopolymers, the review was complemented using papers that discuss this behavior in Portland cement (PC) and based on the main properties that can influence the formation of efflorescence. In this paper, to understand the nature of efflorescence, upon which proper methods of minimizing of this issue can be based, the following aspects are discussed and re-examined: (1) the development of efflorescence's in PC concrete, (2) the role of alkalis in AACs, (3) efflorescence in AACs, and (4) effect from a physical and microstructural point of view of efflorescence's on the ACCs. This paper highlights that the nature of the pore structure and the design parameters (such as alkali concentration, presence of soluble silicates, and water content in the activator) are the two most important factors that control efflorescence rate and changes in mechanical behavior. However, the stability of the alkalis and their relationship with the formed gel, which are determining factors in the formation of efflorescence, remain not completely understood. In the same way, the effect of efflorescence in tensile strength and shrinkage needs to be evaluated.

Liquid Radioactive Solidification Technologies

This review provides a brief analysis of familiar and tested technologies of liquid radioactive waste solidification. The technologies of bituminization, vitrification and incorporation of radioactive waste into the polymer matrix are considered. The paper presents the efficiency indices of the conventional cementation technology and sets forth the results of calculating the cost of components for cementing liquid radioactive waste of various concentrations. Besides, there are results of calculating the volumetric characteristics of cement stone for water-cement relations used for cementing liquid radioactive waste. The review includes the results based on the development and implementation of solidification technologies for liquid radioactive waste using contact-hardening binders that form a durable waterproof stone at the time of pressing and do not require additional water for curing. Generated compounds for immobilization of liquid radioactive waste from nuclear power plants are tested to identify their strength characteristics, resistance to irradiation and leaching parameters. The paper covers the calculation of the cost of components for the solidification of liquid radioactive waste of various concentrations. The developed technology of liquid radioactive waste solidification allows obtaining compounds with strength up to 40 MPa. The volume of the final product is increased by 1.8 times, and the leaching rate is in the range of 1.10×10–4…9.5×10–5 kg/m2 per day.

Development of a New Clean Development Mechanism Methodology for the Quantification of Greenhouse Gas in Calcium Sulfoaluminate Cement

The purpose of this research was to probe beyond the scope of the “National Strategy Project on Carbon Mineralization” to develop a “United Nations Framework Convention on Climate Change, Clean Development Mechanism” (UNFCCC CDM) methodology that enables reduction of greenhouse gas (GHG) by “green cement” under the calcium sulfoaluminate (CSA) cement technologies. The findings will be utilized as the foundations and developed into the UNFCCC CDM project. There were two existing methodologies related to cement, but neither was applicable for CSA cement. The existing methodologies are applicable only when there is one clinker, but CSA cement utilizes more than one clinker. Through this research, we developed methodologies to use waste-based material for avoiding emission leakage and utilized more than one clinker to calculate GHG emissions and reduction. For this purpose, we utilized the CSA cement methodology for calculating GHG reduction compared to Portland cement and found that CSA cement allowed for a reduction of 0.281 tCO2-eq/ton above the reduction enabled by Portland cement. We are presently preparing to register the CSA cement methodology for UNFCCC CDM methodology approval. With the technology transfer and support for this CSA cement technology and methodology, developing countries will be able to achieve their national GHG reduction targets and gain carbon credits. Thus, CSA cement technology could serve as an important tool to deal with GHG emissions and climate change.

Advancements in Properties of Cements Containing Pulverised Fly Ash and Nanomaterials by Blending and Ultrasonication Method (Review- Part II)

The second part of this review paper will explain Hydration properties of Portland pulverised fly ash cement section, Effect of nanomaterial on setting–time section, Effect of nanomaterial on heat of hydration section, Strength gain mechanisms for hardened Portland pulverised fly ash cement paste and mortar section, Effect of nanomaterial on compressive strength section, Effect of nanomaterial on flexural strength (Bending) section, and Conclusion section. Experiments reported include the setting–times, the heat of hydration, the compressive strength gain, and the flexural strength gain in the current article. According to the result, nanoparticles, especially the GNP, increase the heat of hydration of cement, and accelerate the time of setting evidently, both initial and final setting-time. The most effective nanoparticle on early compressive strength gain and flexural strength gain is the GNP. The article also points the effects of the nanoparticles on the strength gain of cement comprehensively. Consequently, the prominent cement technology can use the nanoparticles dispersed in liquid by ultrasonication method to increase the properties of cement based materials effectively.

Recent Progress in Green Cement Technology Utilizing Low-Carbon Emission Fuels and Raw Materials: A Review

The cement industry is facing numerous challenges in the 21st century due to depleting natural fuel resources, shortage of raw materials, exponentially increasing cement demand and climate linked environmental concerns. Every tonne of ordinary Portland cement (OPC) produced releases an equivalent amount of carbon dioxide to the atmosphere. In this regard, cement manufactured from locally available minerals and industrial wastes that can be blended with OPC as substitute, or full replacement with novel clinkers to reduce the energy requirements is strongly desirable. Reduction in energy consumption and carbon emissions during cement manufacturing can be achieved by introducing alternative cements. The potential of alternative cements as a replacement of conventional OPC can only be fully realized through detailed investigation of binder properties with modern technologies. Seven prominent alternative cement types are considered in this study and their current position compared to OPC has been discussed. The study provides a comprehensive analysis of options for future cements, and an up-to-date summary of the different alternative fuels and binders that can be used in cement production to mitigate carbon dioxide emissions. In addition, the practicalities and benefits of producing the low-cost materials to meet the increasing cement demand are discussed.

Перспективы использования помольного пневмотранспортного комплекса в технологии бетонов и цементов

Перспективы использования помольного пневмотранспортного комплекса в технологии бетонов и цементов