After 112 days of curing in 50% relative humidity, the drying shrinkage of controlled concrete was higher than metakaolin concrete by approximately 20%. Figure-4 show the drying shrinkage of both controlled and metakaolin concrete at different ages up to 112 days. Fig.4: Drying Shrinkage of Controlled Concrete and Metakaolin Concrete ...
WhatsApp: +86 18221755073
This decrease can be attributed to the role of DT and MK in increasing both surface area and activation rate of AADW. A similar trend has been reported previously, where increasing the fineness of cement constituents led to a significant loss in workability, especially at constant mixing water content [43].
WhatsApp: +86 18221755073
As a starting material for the production of the geopolymer metakaolin, slag or alumosiliceous fly ash are commonly used [7,8]. Metakaolin is a dehydroxylated form of the clay mineral kaolinite and its structure is based on an amorphous (non-crystalline) aluminosilicate network, which can be activated by a base to form a corresponding geopolymer.
WhatsApp: +86 18221755073
To decouple the effect of aluminium contribution from Portland cement (C 3 A phase) and metakaolin, some systems were prepared using pure C 3 S + LC 2 (combination of limestone, calcined clay and gypsum). ... This suggests that the pH of the pore solution might play a role in the formation of one or another type of CO 3-AFm phases [27]. In OPC ...
WhatsApp: +86 18221755073
Corrosion of concrete sewer pipes by sulfuric acid attack is a problem of global scope. The current paper aims at evaluating two supplementary cementing materia
WhatsApp: +86 18221755073
Sensible thermal energy storage using concrete as a storage medium is a promising technology that helps minimize energy in power plant. The purpose of this study is to evaluate the potential benefits of metakaolin (MK) as a partial substitute for fly ash-based geopolymer for heat resistance. As a partial substitute (5 and 20 wt.%) for fly ash (FA), nine …
WhatsApp: +86 18221755073
Therefore, this study investigates the role of carbonates on the hydration, strength and durability in Portland-metakaolin cement. A total of six blends comprising three carbonate (limestone, dolomite and magnesite) and three non-carbonate (fly ash, quartz and metakaolin) sources were selected to determine the deviations arising in the ...
WhatsApp: +86 18221755073
While most research focuses on the effect of SCMs on cement hydration, the role of the cement on SCM pozzolanicity should also be acknowledged. Work by Cyr et al. [77] has shown, for example, that the pozzolanicity of metakaolin is reduced in low-C 3 A cements.
WhatsApp: +86 18221755073
Metakaolin, produced by calcining kaolinite at high temperature, is a pozzolanic material, suitable to be used in concrete mixes. This paper reviews the research published on …
WhatsApp: +86 18221755073
The role of temperature of metakaolin/Portland cement binary system was studied by isothermal calorimetry. Sample with 50 % of metakaolin replacement were monitored at 30 °C, 40 °C, 50 °C and ...
WhatsApp: +86 18221755073
The hydration reactions of the cement are very complex and there is no single method that determines these reactions. For this reason, a few supplement techniques for various properties and hydration reactions of Portland–composite cement, which are silica fly ash and limestone, containing metakaolin were used in present study. In the first step, the physical, …
WhatsApp: +86 18221755073
Chloride binding is a complex phenomenon in which the chloride ions bind with hydrated Portland cement (PC) phases via physical and chemical mechanisms. However, the current utilization of clays as (Al)-rich …
WhatsApp: +86 18221755073
metakaolin in concrete positively influences durability properties such as penetrability (water absorption, gas permeability and chloride ingress), and helps mitigate ASR.
WhatsApp: +86 18221755073
TG results showed that metakaolin promoted the formation of additional hydration products at 3d, implying that the pozzolanic reaction of metakaolin was accelerated. MIP …
WhatsApp: +86 18221755073
The microstructure properties of Metakaolin-UHPC play a crucial role in determining its overall performance, including its strength, durability, and resistance to cracking. ... Adding 5 wt% nano-metakaolin to cement mortar with 30 wt% FA reduced the water permeability coefficient by 73 % at 7 days compared to cement mortar with 30 wt% FA added, ...
WhatsApp: +86 18221755073
Metakaolin has been shown to play a significant role in the pore structure evolution of cementitious materials due to its high pozzolanic reactivity and small fineness.
WhatsApp: +86 18221755073
The concrete mix proportions were produced using a water to cement ratio of 0.5, as illustrated in Table 4. The weights of cement (cement content 400 kg/m 3), gravel, sand, water and superplasticizer for one liter were 400.0 g, 720.0 g, 1080.0 g, 200.0 g and 2.0 g respectively. Firstly, to make SF concrete, ingredients were blended using a ...
WhatsApp: +86 18221755073
1 1 The Role of Zinc in Metakaolin-Based Geopolymers 2 Lei Wang1,2,3, Daniel A. Geddes1, Brant Walkley1,4, John L. Provis1, Viktor Mechtcherine3, 3 Daniel C.W. Tsang2, * 4 5 1 Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield 6 Building, Mappin St, Sheffield S1 3JD, United Kingdom. 7 2 Department of Civil and …
WhatsApp: +86 18221755073
AbstractOnce sulfates become limited, the interaction of limestone with metakaolin (MK) is initiated, resulting in the formation of carboaluminates in a blended cement system. In this study, two different types of MKs (sourced from coal mining residue and ...
WhatsApp: +86 18221755073
Hence, there is an increased need for alternate binder systems with the ability to reduce the effects of chloride attack in concrete. This paper presents a critical review of the …
WhatsApp: +86 18221755073
Properties of the alkali activated slag cement with a modifying additive—metakaolin—added in a quantity of 10 % by mass are reported and discussed. ... O., Kavalerova, E. (2015). Role of Metakaolin on Lowering pH of the Alkali Activated Cement Concrete in Barrier Application. In: Scrivener, K., Favier, A. (eds) Calcined Clays for ...
WhatsApp: +86 18221755073
Metakaolin had a low influence on reducing the deterioration of the compressive strength of basalt concrete up to 300 °C. Otherwise, it negatively influenced the compressive strength at 500 °C; it explained the role of metakaolin on cement gel dehydration in reducing the compressive strength.
WhatsApp: +86 18221755073
While batching of concrete consumes about 1 billion tons of mixing water annually, more than half of the global population will suffer from a shortage of drinking water by 2025 [6]. ... Normally, alkalinity plays a critical role in the dissolution rate …
WhatsApp: +86 18221755073
The Blaine value of metakaolin is higher in comparison to PCC. While the Blaine value of PCC is 3670 cm 2 /g, the Blaine value of 20% metakaolin–substituted cement increases up to 4752 cm 2 /g (Table 2). Because the specific gravity of metakaolin is smaller than PCC, it reduces the specific gravity of 20% metakaolin–substituted cement.
WhatsApp: +86 18221755073
In recent years, the utilization of supplementary materials has played an important role in development of high strength concrete, improving the overall properties of concrete and rendering sustainability to concrete construction. ... Compressive strength, chloride diffusivity and pore structure of high performance metakaolin and silica fume ...
WhatsApp: +86 18221755073
As a low-carbon alternative to the traditional portland cement, geopolymers are produced via the alkali-activation of aluminosilicate precursor powders, normally metakaolin or fly ash. By eliminating the processes of limestone decomposition and high-temperature calcination during the cement manufacturing, the production of geopolymers could ...
WhatsApp: +86 18221755073
The optimization of metakaolin (MK) in pre-cured geopolymer concrete involves developing predictive models to capture the interplay of various influencing factors and guide …
WhatsApp: +86 18221755073
The usage of metakaolin in Portland cement-based materials is very common, but there are only very a few studies on metakaolin blended MPC [25], [26], [27]. Judged from the previous results, metakaolin can significantly increase the strength, prolong the setting time and improve the water resistance of MPC [22].
WhatsApp: +86 18221755073
The role of Zn, a known retardant used in Portland cement, in geopolymer systems is not well understood. This study scrutinises the effect of Zn on metakaolin-based geopolymer reaction mechanisms and kinetics, and investigates the incorporation mechanism of Zn in …
WhatsApp: +86 18221755073
Metakaolin improves the mechanical properties and durability of MPC. Metakaolin decreases the early-term hydration heat of MPC and the total porosity. Mechanisms of …
WhatsApp: +86 18221755073
A ternary system comprising Ca20Al26Mg3Si3O68 (Q-phase), limestone, and metakaolin is proposed, and its hydration behavior, hydration product phases, microstructure, and mechanical properties are investigated and compared with pure Q-phase cement. The results indicate that the ternary system exhibits exceptional and sustained compressive strength even …
WhatsApp: +86 18221755073
Alsallami [63] found that the presence of 10%NMK in normal concrete played a vital role in reducing the deterioration due to the sulfates action. Zhang et al.found that nanometer metakaolin could improve the frost resistance [110, 134], acid rain erosion resistance [135] and electrical conductivity [118] of cement-based
WhatsApp: +86 18221755073
In recent years, the utilization of supplementary materials has played an important role in development of high strength concrete, improving the overall properties of concrete and rendering sustainability to concrete construction. Though different supplementary materials such as fly ash, silica fume, metakaolin and ground granulated blast furnace slag have been utilized …
WhatsApp: +86 18221755073
This research demonstrated the influence of integrating glass aggregate and metakaolin wherein coarse aggregate was substituted by 10%, 15%, 20%, 25%, and 30% glass cullet (by weight), and cement ...
WhatsApp: +86 18221755073
Title: Metakaolin in Concrete: The Role of Alumina Author(s): Michael Thomas Publication: Web Session Volume: Issue: Appears on pages(s): Keywords: DOI: Date: 10/17/2021 Abstract: Data are presented from a number of studies on the durability of mortar and concrete containing metakaolin (MK), a calcined high-purity kaolin clay (kaolin: Al2O3·2SiO2·2H2O).
WhatsApp: +86 18221755073
The major oxide composition of both Portland cement (PC) and metakaolin (MK) is presented in Table 1. The true densities of the Portland cement and metakaolin, determined by a Helium Pycnometer, were 3.18 and 2.53 g/cm 3, respectively.
WhatsApp: +86 18221755073
Download Citation | Effects of metakaolin on the hydration development of Portland–composite cement | The hydration reactions of the cement are very complex and there is no single method that ...
WhatsApp: +86 18221755073
Kaolin, also known as China clay, is one of the materials that can be used as partial replacement for Portland cement but most of the research has been focused on its dehydroxylated form (metakaolin).
WhatsApp: +86 18221755073