Concrete Superplasticizer Research Articles

A Review on Concrete Superplasticizers and Their Potential Applications for Enhancing the Performance of Thermally Activated Recycled Cement.

With the rapid development of the construction industry worldwide, a large amount of waste concrete is generated each year, which has caused serious environmental problems. As a green and sustainable building material, thermally activated recycled cement (RC) has received widespread attention. However, the unique properties of RC, such as the high water demand and short setting time, necessitate the use of specialized superplasticizers that are different from those used in ordinary Portland cement. As an important component for the application of RC, superplasticizer has an important impact on the performance modification of RC. This article summarizes the recent research progress of potential superplasticizers for RC, with a view to providing a reference for the research and application of superplasticizers for RC. Based on the differences between ordinary Portland cement and RC, the paper discusses potential superplasticizers that may be suitable for RC, and points out that future development of potential modified superplasticizers can include altering the molecular structure to improve adsorption onto the surfaces of RC or to enhance the durability of concrete with RC.

Unraveling polycarboxylate superplasticizer (PCE) compatibility in muscovite-blended cement paste through aggregation mechanisms

Muscovite is a common harmful mineral in manufactured sand, and has always led to the poor compatibility of superplasticizers in fresh concrete. Currently, the failure mechanism is usually explained by competitive adsorption and interlayer adsorption. In addition to the adsorption point of view, as a kind of surfactant, the self-aggregation conformation of superplasticizers in solutions also requires attention. This study explored the compatibility of polycarboxylate superplasticizer (PCE) in cement paste containing muscovite and explained the failure mechanism from the PCE aggregation point of view. Results showed that at the saturated dosage of PCE (0.14 wt%), the introduction of 6 wt% muscovite resulted in a complete loss of fluidity. In the pore solution of cement paste blended with muscovite, the PCE exhibited a lower critical micelle concentration (CMC) and larger aggregation size. The aggregation of PCE is due to the high ionic concentration in cement paste with muscovite, which increases the hydrophobic interaction between PCE and counter ion.

Atomistic Insight on Effect of Silica Fume on Intermolecular Interactions between Poly(carboxylate) Superplasticizer and Calcium Ions in Concrete.

Understanding how poly(carboxylate)s of chemical admixtures interact with calcium ions in cement pore solutions in the presence of silica fume is fundamental to developing better chemical admixtures for concrete production. In this work, the intermolecular interactions of calcium ions with a poly(carboxylate) superplasticizer type of chemical admixture was investigated via classical all-atom molecular dynamics (MD) simulations and Density Functional Theory (DFT) calculation methods in the presence of silica fume. The classical all-atom MD simulation and DFT calculation results indicate that calcium ions are interacting with oxygen atoms of the carboxylate group of PCE. The better interaction energy could mean an improved adsorption of the PCE segment with calcium ions. In this regard, it can be noted that the ester-based PCE segment could have a better adsorption onto calcium ions in comparison with the ether-based PCE segment. Moreover, the presence of silicon dioxide could improve the adsorption of the PCE segment onto calcium ions.

Preparation and Properties of Polycarboxylate Superplasticizer Based on Chain Transfer Agents with Various Structures

AbstractPolycarboxylate superplasticizer (PCE) is a common admixture in high performance concrete. In the design of PCE molecules, it is necessary to ensure that the molecular weight of the polymer is moderate and the acid‐ether ratio is appropriate to improve the dispersion effect. Chain transfer agent is usually added in the synthesis of PCE to adjust the molecular weight and distribution of PCE. In this study, three sulfhydryl chain transfer agents with different electron‐withdrawing groups or electron‐donating groups were synthesized by nucleophilic addition reaction based on sodium hydrosulfide method. Then, three kinds of PCE containing sulfhydryl chain transfer agent were prepared and compared with commercial β‐mercaptopropionic acid superplasticizers. The yield stress and plastic viscosity of cement paste samples prepared by PCE−A and PCE−M were close to those prepared by PCE−P. PCE−M and PCE−A prepared by chain transfer agent with electron‐withdrawing group had higher dispersion and retention capacity than PCE−P, and had more obvious delay of cement hydration and lower hydration accumulated heat. Therefore, the optimization of molecular structure of chain transfer agent is helpful to improve the properties of concrete superplasticizer.

Aloe Vera-Based Concrete Superplasticizer for Enhanced Consolidation with Limestone Calcined Clay Cement

Self-consolidating concrete (SCC) is renowned for its outstanding workability and ability to seamlessly flow into intricate structures with minimal vibrations, achieved through the incorporation of chemical admixtures. This study pioneers an innovative approach by exploring the use of the cost-effective and readily available plant extract aloe vera mucilage (AVM) as a bio-admixture for SCC. The primary objective is to assess the impact of AVM on SCC formulations, including those comprising ordinary Portland cement (OPC) and blended cement LC3 (clinker 50%, calcined waste clay 30%, limestone 15%, gypsum 5%). AVM is applied at varying dosages at up to 10%. Findings reveal that LC3 exhibits lower consistency, reduced slump values, and extended initial and final setting times compared to OPC. With increasing plasticizer dosage, V-funnel and L-box values decrease. Notably, OPC samples with both plasticizers outperform LC3 in compressive strength at 7, 14, and 28 days. Significantly, a 2.5% AVM dosage demonstrates enhanced compressive strength in both OPC and LC3 samples. In summary, this research positions AVM as an innovative and comparable alternative to commercial plasticizers, contributing to reduced yield stress and increased slump flow in SCC.

The Categories and Application of PCE Superplasticizers in Concrete

Polycarboxylate ether superplasticizers (PCEs) are water reducers in the concrete mix that play a significant function in aspects of reducing the water-to-cement ratio, improving impermeability, increasing compressing strength, and meditating the shrinkage. This paper introduces the characteristics of PCEs, discusses the application, advantages, and disadvantages of concrete, and puts forward some measures. The mechanism of PCEs is the dispersion function of the molecular structure and the neutralization. Currently, PCEs are updated from one generation to another, conventional PCEs mainly include methacrylate ester, isoprenol ethe, and methallyl ether-PCEs. Another two major types of PECs are vinyl ether-based and calcium silicate hydrates PCEs, respectively. The application of PCEs revolutes novel types of concrete, such as ultra-high performance concrete and self-compacting concrete. When applying PCEs, retardation has to be considered. Meanwhile, another drawback of PCEs is that they can hardly work with other admixtures. A novel type that is considered clay properties can be another research field.

Rheological Investigation of a Set of PCE Superplasticizers in Cement

AbstractThe importance of polycarboxylate ethers (PCE) as concrete superplasticizers has significantly increased in recent decades, both technically and commercially. At the least, three descriptors describe the average PCE structure: the side chain length (P), the charge density (N), and the number of repeating units (n). The synthesis parameters determine the average composition of the PCEs and, consequently, their performance in cementitious materials. This study examines the rheological properties of 27 different PCE structures, which were synthesized using redox‐initiated free‐radical copolymerization. We independently varied the parameters P and N and produced three PCEs with different molar weights for each combination of P and N. Cement pastes with low PCE dosages of 0.035 wt% were tested in a rheometer using a plate‐plate geometry. It turns out that when the PCE is added directly to the mixing water, the PCE has a complex influence on the very early hydration. Consequently, the obtained rheology data is not entirely in line with available structure‐activity relationships. Additionally, we attempted to model the observed rheology data based on three structural PCE descriptors. While a multivariate linear regression model failed to accurately describe the relationship, a random forest model delivered a better model. In summary, we conclude that the impact of PCEs on early hydration significantly affects the rheology of the paste. The changed hydration pathway causes a deviation of our results from existing structure‐activity relationships and makes it challenging to statistically model the sparse rheology data with a minimal set of three structural descriptors.

Toward clima-resilient ultra-high performance concrete (UHPC): A survey on high-strength mortars engineered with extra-low dosage graphene-based materials (GBMs)

Latest advances showed that ultra-high performance concrete (UHPC) holds the potential to meet the criteria of future civil infrastructures. Several nanofillers (NFs) proved to enhance the performance of UHPC in terms of economic and environmental sustainability and even assigning novel features. Presently, this promising approach is still in its early stage. In this perspective, mortars based on Portland cement CEM I 52.5 N were engineered with extra-low dosage (0.01% by weight of cement) graphene nanoplatelets (GNPs) or nanographite (nG). An acrylic superplasticizer for high-strength concrete was used as additive. Fresh properties of the cementitious admixtures were characterized by viscosity measurements, flow table and bleeding tests. Prismatic specimens were hardened in water at room temperature for 28 days. Microstructure was observed by Scanning Electron Microscopy, the pore structure and specific surface area (SSA) investigated by Mercury Intrusion Porosimetry (MIP) and nitrogen adsorption-desorption measurements, thermal behavior studied by thermogravimetry, and mechanical strength evaluated by compression and bending tests. Electrical resistivity was determined by Electrochemical Impedance Spectroscopy (EIS). Both 2D-NFs induced a slight lubricant effect that did not significantly affect neither workability nor bleeding. GNPs do not appreciably impact on the mechanical properties of the hardened nano-engineered materials, a decay of bending strength was observed only for nG-loaded samples. The positive impact of the extra-low dosage GNPs on the hardened mortars was clearly detected by MIP and EIS in terms of reduced porosity (−31%), improved bulk density (+5.7%), pore refining (median and average pore diameter −35% and −9%, respectively), increased resistivity (+97%) and lowered predicted intrinsic permeability (−52%). In the same experimental condition, nG-engineered mortars suffered from uneven dispersion that led to increased porosity and pore coarsening.

Kinetics of glycerol and polyglycerol maleates production: Raw materials for partially bio-based concrete admixtures

In this work, the self-catalyzed kinetics to produce glycerol, diglycerol, and polyglycerol-4 maleate esters were experimentally determined from 60 ºC to 80 °C. These esters can be used as intermediates in the production of partially bio-based admixtures that can replace petroleum-derived polycarboxylate ethers, which are traditionally used as concrete superplasticizers. The obtained experimental data were used to adjust the kinetic model parameters for the three reactions, including the effect of temperature. The model adequately predicted the behavior of the three proposed reactions, which was statistically validated using the Fisher-Snedecor test. The activation energies of glycerol, diglycerol, and polyglycerol-4 maleate were 29.5, 85.5, and 68.9 kJ/mol, respectively, with frequency constants of 7.93 × 102, 2.02 × 1011, and 4.48 × 108 min−1. The highest activation energy was obtained for the esterification of maleic anhydride (MAH) with diglycerol, indicating that this reaction is more temperature dependent. The kinetic constants at 70 °C were 2.56 × 10−2 min−1, 1.92 × 10−2 min−1, and 1.46 × 10−2 min−1 for the esterification of MAH with glycerol, diglycerol, and polyglycerol respectively, showing a greater reaction rate for the esterification with glycerol.

Novel concrete superplasticizers with sterically hindered amines as stabilizing pendant side chains

In this work, a sterically hindered amine, 2,2,6,6-tetramethyl-4-piperidyl methacrylate (TMPMA), is introduced as a bulky pendant group to achieve steric hindrance, replacing the traditional poly(ethylene oxide) (PEO) side chains of traditional polycarboxylate ether (PCE) superplasticizers (SPs). Note that PCE is the common name for concrete superplasticizers having both carboxylic acid and PEO side-chains in which the bulky PEO pendant group exert large steric hindrance leading to good dispersion and stabilization of cement particles. In this work, the PEO side chains are replaced by a sterically hindered amine. Therefore, copolymers of methacrylic acid (MAA) and TMPMA with different molar ratios were prepared by Reversible-Addition Fragmentation Chain Transfer polymerization (RAFT). The prepared copolymers were characterized by proton nuclear magnetic resonance (1H NMR) and size exclusion chromatography (SEC) to elucidate the chemical structure and molecular weights. Rheological studies and fluidity measurements revealed that poly(MAA-co-TMPMA) SPs, which we introduce here as polycarboxylate amine (PCA) SPs, enhanced cement flowability, workability, and slump retention. Free radical polymerization (FRP) was also employed, as an industrially more relevant, more straightforward and more cost-effective synthesis technique, for the preparation of PCA SPs to reflect the possibility of scaling up these SPs via conventional polymerization methods. The resulting FRP PCA analog exhibited the same plasticizing efficacy as those prepared by RAFT polymerization, demonstrating that these polymers could have high potential in the concrete industry.

Novel concrete superplasticizers containing crown ether pendant side chains for improved cement paste workability

In this work, new concrete superplasticizers based on crown ethers as the bulky pendant side chains have been prepared. First, reversible addition-fragmentation chain transfer (RAFT) polymerization of methacrylic acid (MAA) and pentafluorophenyl methacrylate (PFPMA) was performed to prepare poly(MAA-co-PFPMA) as a precursor. A subsequent transesterification reaction with hydroxymethyl-crown ethers (CR) was performed to prepare poly(MAA-co-CR) superplasticizers with different crown ether side chains, namely 12-crown-4 (12CR4), 15-crown-5 (15CR5), and 18-crown-6 (16CR6). The prepared copolymers were characterized using nuclear magnetic resonance (NMR) spectroscopy and size exclusion chromatography (SEC) to confirm their structure and elucidate their molecular weights, respectively. Rheological studies and fluidity measurements revealed that the ring size of crown ether plays a crucial role in enhancing the dispersion and workability retention of cement pastes. It has been found that a moderate ring size can result in the highest cement flowability and workability retention performance, and thus polymers with this pendant group could be of potential interest in the concrete industry as novel superplasticizers containing new pendant groups.

Bottling Liquid-Like Minerals for Advanced Materials Synthesis.

Materials synthesis via liquid-like mineral precursors has been studied since their discovery almost 25 years ago, because their properties offer several advantages, for example, the ability to infiltrate small pores, the production of non-equilibrium crystal morphologies or mimicking textures from biominerals, resulting in a vast range of possible applications. However, the potential of liquid-like precursors has never been fully tapped, and they have received limited attention in the materials chemistry community, largely due to the lack of efficient and scalable synthesis protocols. Herein, the "scalable controlled synthesis and utilization of liquid-like precursors for technological applications" (SCULPT) method is presented, allowing the isolation of the precursor phase on a gram scale, and its advantage in the synthesis of crystalline calcium carbonate materials and respective applications is demonstrated. The effects of different organic and inorganic additives, such as magnesium ions and concrete superplasticizers, on the stability of the precursor are investigated and allow optimizing the process for specific demands. The presented method is easily scalable and therefore allows synthesizing and utilizing the precursor on large scales. Thus, it can be employed for mineral formation during restoration and conservation applications but can also open up pathways toward calcium carbonate-based, CO2 -neutral cements.

Absorption behavior of polycarboxylate superplasticizer with different molecular structures on montmorillonite

Polycarboxylate (PCE) is a high performance superplasticizer for modern concrete. With the high quality sand becoming precious, more and more low quality sands are used in concrete. However, low quality sands generally contain a relatively high content of montmorillonite (MMT), which could seriously reduce the efficiency of PCE. In order to develop PCE suitable for concrete with low quality sands, the absorption behavior on MMT of PCE with different side chains and acid/ether ratio was investigated. In order to explore the effect of MMT on PCE, two macromonomers were selected, isoprene glycol ether 400(TPEG400) and isoprene glycol ether 2400 (TPEG2400), to synthesize six long and short side chain comb-type PCEs with acid-ether ratios of 1.5:1, 2.5:1 and 3.5:1, respectively. The MMT tolerance mechanism of comb-type PCE in MMT-containing cement slurry was examined by FT-IR, DLS, TOC and other analysis. The PCE with long side chain is much easier to be inserted into the layered structure of MMT, resulting in intercalation absorption. The absorption amount of two kinds of side chain PCE on the MMT particles decreased as the acid ether ratio increases. PCE with long side chains showed shear-thickening properties in MMT-containing cement slurry, on the contrary, short side chains showed shear-thinning properties.

Mechanical and durability studies of high performance concrete (HPC) with nano-silica

Concrete is the commonly used building material everywhere but it’s maintenance in severe exposure areas are really challenging for engineers. In order to attain better performance throughout its lifetime without detrimental to its quality, it is recommended to use HPC. HPC is mostly preferable for its durability and strength which is suiTable for long term structures and heavily loaded bridges. In this project, a mix ratio is arrived for high graded concrete and an optimum percentage of silica fume (SF) is added as pozzolanic reactor. Nano silica (nS) is a suiTable cementitious material for packing the voids in concrete and added in various proportions to improve the density and impermeability. Adding up of nS and SF may reduce the ease of work to fulfil the needs of fresh concrete super plasticizer (CONPLAST SP430 G8) is used. The durability and mechanical properties of HPC with varying parameters was studied. The optimum level of ns in HPC was found by considering the relevant tests.

EFFECTS OF BIO-BASED PLASTICIZERS, MADE FROM STARCH, ON THE PROPERTIES OF FRESH AND HARDENED METAKAOLIN-GEOPOLYMER MORTAR: BASIC INVESTIGATIONS

Conventional superplasticizers based on polycarboxylate ether (PCE) show an intolerance to clay minerals due to intercalation of their polyethylene glycol (PEG) side chains into the interlayers of the clay mineral. An intolerance to very basic media is also known. This makes PCE an unsuitable choice as a superplasticizer for geopolymers. Bio-based superplasticizers derived from starch showed comparable effects to PCE in a cementitious system. The aim of the present study was to determine if starch superplasticizers (SSPs) could be a suitable additive for geopolymers by carrying out basic investigations with respect to slump, hardening, compressive and flexural strength, shrinkage, and porosity. Four SSPs were synthesized, differing in charge polarity and specific charge density. Two conventional PCE superplasticizers, differing in terms of molecular structure, were also included in this study. The results revealed that SSPs improved the slump of a metakaolin-based geopolymer (MK-geopolymer) mortar while the PCE investigated showed no improvement. The impact of superplasticizers on early hardening (up to 72 h) was negligible. Less linear shrinkage over the course of 56 days was seen for all samples in comparison with the reference. Compressive strengths of SSP specimens tested after 7 and 28 days of curing were comparable to the reference, while PCE led to a decline. The SSPs had a small impact on porosity with a shift to the formation of more gel pores while PCE caused an increase in porosity. Throughout this research, SSPs were identified as promising superplasticizers for MK-geopolymer mortar and concrete.

Global concrete superplasticizers market (2020 to 2025)

Global concrete superplasticizers market (2020 to 2025)

Effect of Partial Replacement of River Sand by Quarry Dust and Cement by GGBS with Super Plasticizer in Concrete for Sustainability

Effect of Partial Replacement of River Sand by Quarry Dust and Cement by GGBS with Super Plasticizer in Concrete for Sustainability

The Influence of Calcareous Fly Ash on the Effectiveness of Plasticizers and Superplasticizers

Due to the rational shaping of the environment and the management of environmental resources in accordance with the principle of sustainable development, calcareous fly ash (CFA)—high-calcium as a by-product of lignite combustion—is a valuable addition to concrete. This additive, however, due to its high-water demand lowers the workability of the concrete mix, which is a problem, especially in the first 90 min after mixing the components of the mix. In order to meet this challenge, plasticizers (P) and superplasticizers (SP) for concrete are used with various effects which are designed to reduce the yield value and plastic viscosity. To check the technical efficiency of admixtures P and SP with different chemical bases, the main objective of this research was to investigate the influence of raw and ground CFA on the rheological properties and other side effects of admixtures, such as the amount of air in the mixture and the amount of heat of hydration. The use of P, particularly SP, effectively improves the workability of the mortar containing CFA, especially ground CFA. With these admixtures, it is possible to obtain mortars containing ground CFA with similar rheological properties to mortars without its addition. To obtain a specific workability of mortar with CFA, it is usually necessary to introduce a higher dose of P or SP than used for mortars without CFA. The presence of raw CFA does not alter the effectiveness of P and strongly reduces the effectiveness of SP. The reduced effectiveness of SP manifests primarily as a high workability lost. The presence of ground CFA does not change the effectiveness of P (or is higher). The effectiveness of the superplasticizer SNF (with a chemical base of naphthalene sulfonate) and PE (with a chemical base of polycarboxylate ether) is slightly lower or does not change. The effectiveness of the superplasticizer SMF (with a chemical base of melamine sulfonates) is significantly lower. We found that the presence of ash affects the efficiency of P and SP, while processing via the grinding of ash makes the effect negligible. These results are novel in both their cognitive and practical aspects.

Compatibility Assessment of Commercial Cements with superplasticizers

In the present study, compatibility assessment of commercially available cements (OPC and PPC) and SNF & PCE based super plasticizers are made by evaluating the workabilities, setting times and compressive strengths of M40 grade concrete mixes made with two different brands of cement and with two different chemical admixtures. The dosage of SNF and PCE based chemical admixtures to be used in M40 grade concrete is determined using marsh cone test. It was found that M40 concrete made with SNF based superplasticizer has achieved desired compressive strength than the concrete made with PCE based superplasticizer. This shows that SNF based superplasticizer is more compatible for M40 grade concrete than PCE based superplasticizer. So it is suggested that for the development of PPC based M40 grade concrete SNF superplasticizers can be used.

Preparation and Properties Study of a Low-Cost Ammonia Carboxylate Concrete Superplasticizer

Polycarboxylate superplasticizer is the water reducing agent that has the best application prospect in concrete engineering. In this paper, a new type of polycarboxylate superplasticizer is prepared and its properties, such as dispersibility and water-reducing rate in cement particles, slump degree and slump extension in concrete and gradual loss are tested. The test results reveal that the water-reducing agent solves the problem that the traditional polycarboxylate superplasticizer is too sensitive to the change of dosage and that it has good dispersibility to cement particles. The optimum dosage is 2.3%–2.9% and the water-reducing rate is 25.6%–33.0%. The test proves that the high-performance water-reducing agent has a good water-reducing effect. The concrete fluidity of mixed with water-reducing agent is significantly improved and the compressive strength is also improved.