Complex Shear Modulus Research Articles

Development of a Predictive Model for the Indirect Tensile Strength Load–Displacement Curve for Asphalt Mixtures

The indirect tensile (IDT) strength test is one of the common laboratory tests conducted to characterize asphalt mixtures. The IDT load–displacement curve is used to calculate various indicators to evaluate the cracking performance of asphalt mixtures. This study evaluated the effect of the mix composition on the IDT load–displacement curve. Asphalt mixtures with different characteristics, including binder content, binder grade, and mix gradation, were prepared and tested. The study developed statistical regression models to predict the entire IDT load–displacement curve using parameters that describe the mix composition and properties, including the binder complex shear modulus and phase angle, aggregate gradation, and binder content. The results demonstrated that the predicted model parameters were found to correlate well with those calculated from the experimental IDT load–displacement curves. All predicted cracking performance indicators calculated from the predicted IDT load–displacement curve had a strong correlation with those calculated from the measured IDT load–displacement curve. The proposed model can be used as a tool to check the preliminary cracking performance of the asphalt mixtures during the mix design stage. In addition, the mix composition can be adjusted to improve the cracking performance of the designed mix (e.g., adjust binder grade, binder content, gradation, etc.).

Low-frequency MR elastography reveals altered deep gray matter viscoelasticity in multiple sclerosis

IntroductionBrain viscoelasticity as assessed by magnetic resonance elastography (MRE) has been discussed as a promising surrogate of microstructural alterations due to neurodegenerative processes. Existing studies indicate that multiple sclerosis (MS) is associated with a global reduction in brain stiffness. However, no study to date systematically investigated the MS-related characteristics of brain viscoelasticity separately in normal-appearing white matter (NAWM), deep gray matter (DGM) and T2-hyperintense white matter (WM) lesions. Methods70 MS patients and 42 healthy volunteers underwent whole-cerebral MRE using a stimulated echo sequence (DENSE) with a low-frequency mechanical excitation at 20 Hertz. The magnitude |G∗| (Pa) and phase angle φ (rad) of the complex shear modulus G∗ were reconstructed by multifrequency dual elasto-visco (MDEV) inversion and related to structural imaging and clinical parameters. ResultsWe observed φ in the thalamus to be higher by 4.3 % in patients relative to healthy controls (1.11 ± 0.07 vs. 1.06 ± 0.07, p < 0.0001). Higher Expanded Disability Status Scale (EDSS) scores were negatively associated with φ in the basal ganglia (p = 0.01). We measured φ to be lower in MS lesions compared to surrounding NAWM (p = 0.001), which was most prominent for lesions in the temporal lobe (1.01 ± 0.22 vs. 1.06 ± 0.19, p = 0.003). Age was associated with lower values of |G∗| (p = 0.04) and φ (p = 0.004) in the thalamus of patients. No alteration in NAWM stiffness relative to WM in healthy controls was observed. ConclusionLow-frequency elastography in MS patients reveals age-independent alterations in the viscoelasticity of deep gray matter at early stages of disease.

Study of the Viscoelastic and Rheological Properties of Rubber-Bitumen Binders Obtained from Rubber Waste.

According to scientific research from different countries, crumb rubber obtained from end-of-life tires (ELT) during processing can improve the properties of the asphalt mixture, thereby extending the service life of the road surface. This paper presents the modification of bitumen with industrial rubber waste. The modification of bitumen for roads is considered one of the most suitable and popular approaches. This research paper describes the details of using different types of crumb rubber as bitumen modifiers. The modified bitumen's main physical and mechanical characteristics were determined after conventional tests: penetration and ductility, softening point, and Fraas brittleness point. In order to obtain a rubber-asphalt concrete mixture with improved performance characteristics, the viscoelastic and rheological properties of rubber-bitumen binders and their comparison with polymer-bitumen binders were also studied. The research results show that with increasing temperature, the values of viscosity, shear stress and complex shear modulus of all studied bitumen systems decrease, the values of the phase shift angle increase, and the size of the rubber particles has a greater influence on the properties of bitumen systems.

Biomass waste to produce bio oil as rejuvenator for asphalt based on pyrolysis technology

ABSTRACT The objective of the current study is to research the suitability of using two bio-oils produced from corncob and birch bark as two bio-rejuvenators to regenerate aged asphalt binders. To this end, the pyrolysis characteristics of corncob and birch bark were analysed using a thermogravimetric analyzer. The chemical characteristics of the bio-rejuvenators were then evaluated via an elemental analyzer and the Gas Chromatograph Mass Spectrometer (GC-MS) test. The results revealed the presence of a great quantity of lightly weighted compounds in bio-oils. Pen70 asphalt was used as control asphalt binders. The Rotational Viscometer (RV) test result showed that bio-rejuvenators could help reduce the viscosity of aged asphalt binders. In addition, the Dynamic Shear Rheometer (DSR) experiments revealed that bio-rejuvenators could reduce the complex shear modulus, decrease percent strain recovery, increase non-recoverable creep compliance and restore the fatigue performance of the aged asphalt. The Bending Beam Rheometer (BBR) tests indicated that the cracking performance of the bio-rejuvenated asphalt was also improved compared with the aged asphalt. The Fourier transform infrared spectra demonstrated that the bio-rejuvenators helped reduce the aged asphalt's carbonyl and sulfoxide indexes. In addition, the Gel Permeation Chromatography (GPC) test indicated that bio-rejuvenators reduced the polydispersity and molecular weight of the aged asphalt.

Analysis Of Complex Shear Modulus Asphalt (G*) And Phase Angle (δ) On 60/70 Penetration Asphalt With The Additiion Of Mask Waste Content

The threat to the environment posed by carelessly discarded masks creates a new approach to reduce mask waste generated during the pandemic by recycling. The purpose of this study is to determine the increase in the mechanistic properties of asphalt, so that mask waste can be used as an additive for asphalt, ultimately reducing mask waste generated during the Covid-19 pandemic. Testing mechanistic rheological properties of asphalt using Dynamic Shear Rheometer (DSR) tool. The results showed that 60/70 penetration asphalt added with mask waste with a variation rate of 0% to 3% for the value of the complex shear modulus asphalt (G*) will increase along with the addition of mask waste levels. The phase angle value decreases at the same temperature as the mask waste increases. The temperature value at performance grade (PG) increases along with the increase in mask waste levels.

Rayleigh-Taylor Instability in Soft Viscoelastic Solids.

We present an experimental characterization of the gravity-driven Rayleigh-Taylor instability in viscoelastic solids. The instability creates periodic patterns on the free surface of the soft solids that are distinct from the previously studied elastic Rayleigh-Taylor instability. The experimental results are supported by the linear stability analysis reported here. We identify the dependence of the steady-state pattern of deformations on the gel's geometry, complex shear modulus, and surface tension. This study provides quantitative measures applicable to the design of tunable surface textures, soft machines, and 3D structures.

INVESTIGATION OF MODIFICATION OF PETROLEUM BITUMEN BY RUBBER WASTE

According to scientific research in different countries, rubber granules obtained from rubber waste during recycling can improve the properties of the asphalt mixture, thereby extending the service life of the road surface. This paper presents the modification of bitumen with industrial rubber waste. Modification of bitumen for roads is considered one of the most suitable and popular approaches. This research paper describes the details of using different types of rubber granules as bitumen modifiers. The main physical and mechanical characteristics of the modified bitumen were determined after conventional tests, penetration and ductility, softening point, Fraas brittleness point. In order to obtain a rubber-asphalt concrete mixture with improved performance characteristics, the viscoelastic and rheological properties of rubber-bitumen binders and their comparison with polymerbitumen binders were also studied. The research results show that with increasing temperature, the values of viscosity, shear stress and complex shear modulus of all studied bitumen systems decrease, and the values of the phase shift angle increase, and that the size of the rubber particles has a greater influence on the properties of bitumen systems.

Modifying Effect and Mechanism of Polymer Powder on the Properties of Asphalt Binder for Engineering Application.

For achieving the better modifying effect of polyurethane on asphalt pavement materials, the PUA powder modifier was prepared with fine grinding at the glass transition temperature, and polyurethane-modified asphalt (PUA-MA) with different dosages of modifier was prepared. The impact of the PUA on the physical properties of asphalt binder was studied. The modifying mechanism of PUA on asphalt was explored by investigating the thermal performance and chemical composition of asphalt (thermogravimetric analysis, differential scanning calorimetry test, and Fourier transform infrared spectroscopy). The micrograph of the interactive interface was characterized by scanning an electron microscope. Furthermore, the rheological properties of PUA-MA were also investigated and analyzed. The results indicated that the PUA had a dense structure with few pores on the surface. After mixing with asphalt, it altered the asphalt's internal structure via physical fusion and chemical reaction (carbamate formation). PUA improved the thermal stability of asphalt, enhanced the asphalt's thermal decomposition temperature, and further reduced the thermal mass loss while decreasing the glass transition temperature. The addition and dosage increase in the PUA modifier significantly improved the softening point, viscosity, complex shear modulus, and rutting factor of asphalt. Also, the PUA could improve the elastic recovery ability of asphalt and enhance the rutting resistance of asphalt at high temperatures. However, the crack resistance at low temperatures was not effectively improved (ductility and penetration decreased). When the dosage was 6-9%, PUA-MA had the best high-temperature performance, but asphalt showed poor low-temperature performance at this dosage. This study provides a theoretical reference for popularizing and applying polyurethane as an asphalt modifier in road engineering.

Marginal adaptation, physicochemical and rheological properties of treated dentin matrix hydrogel as a novel injectable pulp capping material for dentin regeneration

BackgroundTreated dentin matrix hydrogel (TDMH) has been introduced as a novel injectable direct pulp capping material. In this regard, this study aimed to evaluate its marginal adaptation, physicochemical and rheological properties for the development of clinically feasible TDMH.MethodsTDMH was applied to the pulp floor of prepared Class I cavities (n = 5), marginal adaptation was assessed by SEM at 1000 X magnification to detect gap between dentin and filling material. Five syringes were filled with TDMH and placed between the compression plates of a universal testing machine to evaluate injectability and gelation time was also evaluated by test vial inverting method. The microstructures of lyophilized TDMH were observed by SEM. Moreover, TDMH discs (n = 5) were prepared and the water uptake (%) was determined based on the equilibrium swelling theory state of hydrogels. Its solubility was measured after one week by the ISO standard method. Rheological behaviours of TDMH (n = 5) were analysed with a rotational rheometer by computing their complex shear modulus G* and their associated storage modulus (G′) and loss modulus (G′’). Statistical analysis was performed using F test (ANOVA) with repeated measures and Post Hoc Test (p = 0.05).ResultsTDMH presented an overall 92.20 ± 2.95% of continuous margins. It exhibited gelation during the first minute, and injectability mean was 66 ± 0.36%. TDMH showed a highly porous structure, and the pores were interconnected with an average diameter about 5.09 ± 3.17 μm. Swelling equilibrium gradually reached at 6 days up to 377%. The prepared hydrogels and maintained their shape after absorbing over three times their original weight of water. TDMH fulfilled the requirements of ISO 6876, demonstrating a weight loss of 1.98 ± 0.09% and linear viscoelastic behaviour with G` 479.2 ± 12.7 and G`` 230.8 ± 13.8.ConclusionsTDMH provided good marginal adaptation, appropriate physicochemical and viscoelastic properties support its use as a novel direct pulp capping material in future clinical applications.

Impact of heat-set and cold-set gelling polysaccharides on potato protein gelation: Gellan gum, agar, and methylcellulose

The plant-based meat market is growing due to concerns about the sustainability of the modern food system. Plant-based meats are often constructed from blends of food biopolymers, such as plant proteins and polysaccharides. This study characterizes the thermal setting properties of potato protein (10%) and polysaccharide (2 wt%) mixtures containing polysaccharides with different reversible gelling behaviors: agar (cold set); gellan gum (cold set); or methyl cellulose (heat set). Each sample was heated above the thermal denaturation temperature of the potato proteins to promote protein unfolding, aggregation, and network formation. The addition of the polysaccharides tended to increase the complex shear modulus of the biopolymer blends before heating but increase or decrease it after heating depending on polysaccharide type. The shear modulus and hardness of the gels formed after heating tended to increase after addition of the cold-set polysaccharides but decrease after the addition of the heat-set polysaccharides, especially at refrigerator temperatures. Differential scanning calorimetry data showed that the potato proteins underwent irreversible denaturation after heating for all samples. Zeta-potential analysis showed that the potato proteins and all polysaccharides were negatively charged under the pH conditions used. There was greater water loss during heating for the composite gels containing methyl cellulose, which may have been due to its increase hydrophobicity at high temperatures. Appearance and microstructure analysis showed that phase-separation occurred after mixing the polysaccharides with the potato proteins, which was attributed to a segregation mechanism. The knowledge obtained from this study may help the food industry to optimize protein-polysaccharide blends to create gels with characteristics and structures that can mimic different plant-based meat products.

Application of the Air-Jet Laser Detection Technology for Asphalt Binders

AbstractA fast and convenient technique for Asphalt Binders was proposed in this paper, which was based on air-jet pressurized and laser to detect the transient deformation and creep recovery of asphalt. Taking five kinds of asphalt and modified asphalt commonly used in China as the research objects, the performance of asphalt were tested and analyzed by adopting the Penetration Test, Dynamic Shear Rheological (DSR) Test, Multiple Stress Creep and Recovery (MSCR) Test and the proposed test technology. The results verified the feasibility of the proposed test technology and the correlation between the traditional tests and the proposed test technology. The results demonstrated that the proposed test technology had good discrimination ability for different kinds of asphalt and could effectively reflect the performance differences. The new test protocol was similar to the Penetration Test. There was a significant correlation between the maximum deformation index and penetration index. The correlation coefficient was above 0.8, and the p value was much less than 0.01. It could be used as a possible alternative to the Penetration Test. The proposed new test was relatively convenient and fast compared with the dynamic shear test. There was a linear correlation between the maximum deflection index and the complex shear modulus G*, and the correlation coefficient between the recovery index and the phase angle is above 0.8, which indicated that the proposed new test and the DSR test had a significant correlation. There was also a good correlation between the creep recovery index of MSCR test and the recovery data of the proposed new test method. The research results provided a new solution for the performance test and evaluation of asphalt in China.

Influence of Modified Stalk Fibers on the Fatigue Performance of Asphalt Binder

The type and content of modified stalk fibers significantly influence the fatigue properties of asphalt binder. In this study, different concentrations of NaOH solution were used to modify stalk fibers, and scanning electron microscopy (SEM) was used to observe the effect of the modified concentration on the fiber morphology. A dynamic shear rheology (DSR) test and a linear amplitude sweep (LAS) test were conducted to analyze the effects of the fiber type and content on various factors such as the complex shear modulus G*, phase angle δ, and fatigue parameters (A35 and B). Consequently, the fatigue life Nf of the fiber asphalt binder was calculated using a viscoelastic continuum damage model. The results show that stalk fibers modified using a 5% alkali solution exhibited the best oil absorption and heat resistance, the asphalt binder with a 1.5%–2% fiber content exhibited the best resistance to fatigue, and the fatigue performance of the asphalt binder with different types of fibers was superior when fiber doping was at 1.5%. Additionally, the fatigue parameter A35 of the modified cotton and corn stover fibers increased by 40.5% and 57.6%, respectively, and the fatigue parameter B decreased by 5.8% and 4.8%, respectively, compared with that of the unmodified stover fibers. Finally, the modified corn stalk fiber asphalt binder with a 1.5% fiber content demonstrated the best fatigue resistance.

The use of bio-oil from biodiesel production for enhancing the bitumen healing

Road pavements are exposed to traffic and temperature effects that produce distress, mainly cracking that leads to pavement failure, after which rehabilitation actions are necessary to extend pavement life. Bio-rejuvenators have been used to recover the bitumen properties lost due to fatigue of the asphalt mixtures and ageing due to temperature variations and oxidation. Thus, this paper investigates the healing of bitumen modified with bio-oil derived from biodiesel production. One base bitumen in three different ageing stages (unaged, short and long-term ageing) was used for adding up to 3% of bio-oil to the bitumen. In addition to consistency and rheological tests to characterise the modified bitumen, fatigue resistance tests with and without rest periods were performed to assess the healing through three indexes, relating the complex shear modulus, the number of cycles to failure and the amount of damage, after a rest period. It was verified that the healing follows an exponential law with the rest period, but the number of cycles in each loading period decreases compared to the previous period. For a 15-minute rest period, the healing was limited to 26.9%, but the bio-oil contributed significantly to that restoration.

Effect of re-aging on chemical and rheological properties of waste engine oil rejuvenated asphalt binder

The use of rejuvenator can potentially restore original properties of reclaimed asphalt pavement (RAP) materials to achieve the purpose of reuse, but less attention has been paid to the aging properties of rejuvenated asphalt binders. In this study, original asphalt binder, aged binder and the rejuvenated binders with 3 %, 6 %, and 9 % of rejuvenator by total weight of binder were prepared first. Then the five rejuvenated binders were subjected to the oven aging. Based on the results from Fourier Transform Infrared Spectroscopy and Dynamic Shear Rheometer, the chemical and rheological properties of the five binders were investigated due to re-aging. It is showed that the of carbonyl index of the rejuvenated binders and original binder increase rapidly during the fast-aging state and then slowly during the constant-aging state, while aged binder increases approximately linearly. The rheological properties indexes such as complex shear modulus, phase angle δ, crossover frequency, crossover modulus, rheological index, G-R parameter and rutting factor of the five binders were determined, and the variation of these indexes are similar or opposite to carbonyl index during aging. Aging performances of the five binders were investigated using the oven aging indexes. It is showed the rejuvenated binders with more dosage of rejuvenator have faster aging rate and more obvious effects on the aging rheological behavior. The rheological properties of the aged binder are less affected by the re-aging. Among the rheological property indexes, the G-R-based oven aging index is most susceptible to the re-aging. There are some certain close relationships between the chemical property change and rheological property evolution during re-aging for the five binders, without considering the aging times and the dosage of rejuvenator.

UV-induced gradient aging of bitumen films: A comprehensive study

The aging of bitumen materials under ultraviolet (UV) radiation is a highly intricate process involving volatilization of components and multiple photochemical reactions. To gain a comprehensive understanding of the mechanism and progression of UV aging in bitumen films within bitumen mixtures, this study investigates the formation and evolution of UV aging gradients in bitumen films from various perspectives, including morphology, composition, macro-, and micro-mechanical aspects. Initially, specific bitumen film specimens were subjected to aging, and a protocol for sample handing and testing was developed. Optical microscopy images, functional group indices, and component contents of the bitumen films were then measured and calculated to track the UV aging process from the surface to the interior. Additionally, profiling micro-mechanical tests and layer-by-layer dynamic mechanical tests were conducted to characterize the variations in mechanical properties induced by UV aging gradients within the bitumen films. The results indicate that UV radiation causes significant volatilization of light components on the film surface, resulting in wrinkling. Concurrently, photochromic reactions take place in both bitumen macromolecules (asphaltenes and resins) and small molecules (saturates and aromatic), while molecular photodegradation may also occur. Fluorescence imaging, infrared spectroscopy analysis, and component determination reveal that the degree of UV aging in the bitumen films increases with radiation time and gradually propagates towards the interior. C-S bonds are more sensitive to UV radiation than C = C bonds, leading to oxidation and the formation of sulfoxide groups. Due to the adsorption of light components by aggregates, the modulus values at the surface of aged bitumen films and the aggregate interface are higher, while the intermediate region exhibits lower values. Rheological indicators demonstrate that UV aging, to a certain extent, results in the decomposition of bitumen molecules, leading to a decrease in complex shear modulus and an increase in phase angle. This work significantly enhances our understanding of the mechanism of UV aging in bitumen films and holds important implications for the design and development of UV-blocking materials.

Shear complex modulus imaging utilizing frequency combination in the least mean square/algebraic Helmholtz inversion

Shear complex modulus imaging utilizing frequency combination in the least mean square/algebraic Helmholtz inversion

Characteristic analysis of a novel magnetorheological fabric composite cored flexible sandwich beam with tunable stiffness

This paper focuses on the performance improvement and evaluation of a novel flexible sandwich beam incorporated magnetorheological fluid porous fabric (MRF-PF). As a novel MR material, MRF-PF has been introduced, prepared, and measured to analyze the pre-yield property between complex shear modulus and magnetic fields. MRF-PF is used into the flexible sandwich beam as core layer. Pre-yield property with tunable stiffness is used to adjust the dynamic response. Then, a theoretical model is derived which can precisely describe the performance. Based on experimental results, sandwich beam incorporated MRF-PF has a good performance of controllability. When the magnetic field is applied into the free end, the natural frequency decreases with increasing the currents and filling ratio. In contrast, the frequency and amplitude increase when the clamped end is exposed to the magnetic fields. Comparing with other investigations, this proposed sandwich beam incorporated MRF-PF has a larger frequency range. The first and second natural frequency show the increases of 54.8% and 77.2%, respectively. The reduction of amplitude is closely related to the thickness of face plate. Therefore, the performance of the compound sandwich beam can be significantly improved by MRF-PF.

CHARACTERIZATION OF ASPHALT MODIFICATION USING GROUND RUBBER AND REACTIVE RUBBER NR-g-MA AS COMPATIBILIZER

This study aims to improve the quality of asphalt by adding ground tyre rubber (GR) and reactive rubber (NR-g-MA) as compatibilizers of asphalt-rubber mixability. The use of GR has been widely used to improve the performance of asphalt and extend the service life of asphalt. The NR-g-MA used was the product of the copolymerization of SIR-20 rubber grafts with maleic anhydrous (MA) through a melting process in an internal mixer. Mixing of GR in asphalt was carried out in an external mixer with composition of asphalt/GR 95/5 phr at the temperature of 180oC for 90 minutes. The performance of asphalts were measured based on conventional test of penetration and softening point. The rheological properties of asphalt were measured using a Dynamic Shear Rheometer (DSR). Important parameters of the rheological properties measured are complex shear modulus (G*) and phase angle (d). Asphalt resistance to the permanent deformation (rutting) were determined on asphalt that has undergone a short-term aging process in a rolling thin film oven (RTFO) and measured at high temperatures (58-82OC). Fatigue crack resistance was tested on asphalt that has undergone a long-term aging process using the method of pressure aging vessel (PAV) and measured at low temperatures (25-31OC). Asphalt-GR mixtures' chemical, thermal and morphological properties were studied using ATR-FTIR, DSC/TGA, and SEM respectively. The results showed that adding used ground rubber (GR) decreased the penetration value by 9.93 – 18.87% and increased the softening point of asphalt from 5.57 – 11.40%. Rheological analysis showed that the addition of GR and compatibilizer NR-g-MA increase the value of complex shear modulus (G*) and decrease the phase angle (d) of the asphalt. The addition of ground rubber and reactive rubber of NR-g-MA to asphalt improve the performance of asphalt because it has rutting resistance at high temperatures as well as improves asphalt cracking resistance at low-temperature measurements. The addition of NR-g-MA reactive rubber to modified asphalt ground rubber can increase the mixability of asphalt-rubber used tires.

Study on rheological properties and damage mechanism of asphalt under acid-alkali precipitation corrosion

This research delved into the effects of pH precipitation on asphalt's rheological characteristics and damage mechanisms. We analyzed the shifts in asphalt's acid-alkali corrosion properties through macro and micro tests. To begin with, we conducted three cycles of bitumen corrosion tests using acidic, alkaline, and neutral solutions. Subsequently, the dynamic shear rheological test (DSR) measured the complex shear modulus, phase angle, and rutting factor before and after asphalt corrosion, revealing correlations between corrosion duration, temperature, and asphalt's rheological traits. Additionally, we evaluated post-corrosion changes in asphalt's functional groups through infrared spectrum testing, allowing us to deduce the underlying damage mechanism. Our results showed that asphalt's deformation resistance was directly related to soaking time and inversely related to temperature. The complex shear modulus exhibited an inverse relationship with temperature, while the phase angle demonstrated a direct proportionality to temperature variations. From a chemical perspective, acidic components within asphalt tend to dissolve and ionize, while alkaline substances undergo esterification and neutralization. Notably, asphalt modified with styrene–butadiene–styrene (SBS) exhibits enhanced resistance against acid and alkali corrosion, surpassing the performance of the 90# asphalt. Ultimately, this research established a theoretical framework for exploring acid-base precipitation resistance in asphalt binders, contributing to our understanding of asphalt's binder properties and broadening its applications.

Chemorheology of a Si/Al > 3 Alkali Activated Metakaolin Paste through Parallel Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA).

Although geopolymers, as structural materials, should have superior engineering properties than traditional cementitious materials, they often need to improve their final characteristics' reproducibility due to the need for more control of the complex silico-aluminate decomposition and polymerisation stages. Thermosetting of a reactive geopolymeric paste involves tetrahedral Silicate and Aluminate precursor condensation into polyfunctional oligomers of progressively higher molecular weight, transforming the initial liquid into a gel and a structural solid. Viscosity and gelation control become particularly critical when the geopolymer is processed with 3D printing additive technology. Its physical state modification kinetics should match the flow and setting characteristics required by the deposition process. The reaction kinetics and the elastic and viscous characteristics preceding gelation and hardening have been investigated for an alkali-activated Metakaolin/Sodium Silicate-Sodium Hydroxide paste with a Si/Al ratio > 3. A chemoreological approach has been extended to these inorganic polymerisable systems, as already utilised for organic thermosetting polymers. Differential scanning calorimetry and Oscillatory DMA were carried out to monitor the advancement of the polymerisation reaction and the associated variations of the rheological viscoelastic properties. Dynamic thermal scans were run at 1 °C/min and a frequency of 10 Hz for the dynamic mechanical tests. The observed kinetics of polymerisation and variations of the elastic and viscous components of the complex viscosities and shear moduli are described in terms of polycondensation of linear and branched chains of oligomeric macromolecules of increasing complexity and molecular weight up to gelation (Gel1) and cross-linking of the gelled macrostructure (Gel2) and final glassy state. Geopolymerization can be allocated into two main behavioural zones: a viscoelastic liquid paste below 32.5% of reaction advancement and a viscoelastic solid above. Initial complex viscosities range from 2.3 ± 0.9 × 10-5 MPa*s to 6.8 ± 0.9 × 10-2 in the liquid-like state and from 1.9 ± 0.1 MPa to 9.6 ± 2.1 × 102 MPa in the solid-like state.