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What Concrete admixtures

Air entrainment is created by design. This process produces air bubbles within the concrete mix through mechanical agitation. But these are not common air bubbles that are irregular and visible to the naked eye. Air-entrained bubbles are microscopic, innumerous, and spherical. Also, they have an evenly spaced distribution. Entrained air bubbles usually maintain a distance of 0.25 mm between each other. In addition, 4% to 6% of these well-distributed air bubbles can be incorporated into cementitious mixtures. This action creates many tiny, closely spaced air bubbles in the hardened concrete. These air-entraining agents include alkali salts from resin acids, sulphonated resin acids, alkali sulphonates, alkyl sulphonates, alkylarenesulphonates, fatty acid salts, etc. One way to increase the workability of cementitious mixes is by simply adding more water. By increasing the water-to-cement ratio, the mixture becomes more fluid. But that decision comes with its problems – like the bleeding of concrete. So, it's time to improve workability with better methods. However, air-entrained concrete has a higher air content than concrete without entrained air. In this manner, the well-distributed air voids act as expansion chambers for the frozen water. Thus, the air voids within air-entrained concrete reduce the probability of microcracks. With air entrainment enabled, the air bubbles within the mixture act as a lubricant within the concrete mix. Thus, increasing the fluidity. The enhanced workability allows the mixture to be pumped and transported to its intended location within the construction site more efficiently. Air-entraining agents reduce the amount of water needed to produce a given slump. At a fixed cement content, this lowers the water-cement ratio, which reduces permeability. Although entrained air bubbles increase the void range of hardened concrete, the air voids aren't interconnected. A pro tip is to include an air-entraining agent in the concrete mix design especially when using artificial sand. Different from natural sand, artificial sand is less spherical and irregularly shaped. Applying the same principle as explained before, the entrained bubbles enhance the fluidity of a concrete mixture with manufactured sand.

Why would an engineer specify an air entrained concrete

Air-entrained concrete is more plastic and workable than non-air-entrained and can be placed and compacted with less segregation and bleeding. Hardened air-entrained concrete is far more resistant to the harmful effects of freezing, thawing, and salt scaling than ordinary concrete. Essentially, concrete comprises four materials: cement, sand, stone, and water. Water is the only liquid and the least dense of these four ingredients. Thus, water not absorbed into cement or sand tends to rise above the more dense materials of the mixture. The result is a puddle of water that "bled" to the surface of freshly poured concrete. Too much-untrained air will have serious adverse effects on the performance of the concrete, e.g., loss of strength and stickiness during finishing. Air entrainment should not be used in interior concrete that will be steel troweled, especially machine troweled. An increase in the amount of fly ash per unit of concrete will decrease the amount of entrained air. Carbon Black • The purposeful addition of carbon black as a colorant for concrete reduces the air content. In most instances, considerable amounts of additional AEA are required to attain specified air levels. Enabled by air-entraining agents, air bubbles increase the surface area water and cement need to cover. The outcome is a more balanced mixture, with less water rising to the surface of freshly placed concrete. Type I-P blocks of cement will entrain less air. Water can do amazing things for concrete, but it can also cause damage. Concrete not adequately prepared for climate variations can suffer from extreme heat and cold. In regions where negative temperatures occur, concrete needs to be able to resist the freeze-thaw cycle. Test your concrete for air content at the point of placement just before you place it.

Can you pump air-entrained concrete

The main reason air-entraining agents are added to concrete mix design is to increase its freeze-thaw resistance. The air bubbles created through air entrainment act as "expansion chambers" for water. Why does water need space to expand? Because frozen water occupies 9% more volume than water at room temperature. If air entrainment did not happen, icy water would make space for itself by creating minuscule cracks within concrete. Over time, this repeated cycle of freezing and melting of water causes micro-fractures to become large-scale problems. Thus, by simply adding air-entraining agents to the concrete mix design, the resistance to freeze-thaw can be significantly increased. Are the limits on air content commonly used (3 to 7% by volume of concrete) considered satisfactory for nearly all purposes? A. In most air-entrained concrete, values between these limits (based on total concrete volume) have been the aim.

Price of Concrete admixtures

Concrete admixtures particle size and purity will affect the product's Price, and the purchase volume can also affect the cost of Concrete admixtures. A large amount of large amount will be lower. The Price of Concrete admixtures is on our company's official website.

Concrete admixtures supplier

If you are looking for high-quality Water-based Concrete Release Agent, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com). We accept payment via Credit Card, T/T, West Union, and Paypal. TRUNNANO will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.

What Polycarboxylate superplasticizer monomer

Commonly used Polycarboxylate Superplasticizer Monomers include isobutylene alcohol polyoxyethylene ether (HPEG or VPEG or XPEG), methoxy polyethylene glycol (MPEG), aryloxy polyethylene glycol (APEG) and translated polyethylene glycol (TPEG). Polycarboxylate Superplasticizer Monomers market reports offer a critical study on the market position of the Polycarboxylate Superplasticizer Monomers manufacturers with facts and figures, definitions, expert opinions, and the latest expansions throughout the globe.

Direct Polycarboxylate superplasticizer monomer

Sun and Huang used direct polymerization to make new PCE, which was directly polymerized using allyl polyethylene glycols, methyl acrylate, maleic anhydride, and ammonium persulfate. The influence of monomer ratio, initiator dosage, reaction time, reaction temperature, and dropping time on the dispersing ability and fluidity-retaining ability of PCE was studied. Based on the orthogonal experiment, the best process was obtained. The comparison was made on the performance of the product synthesized and another widely used product at present, which was synthesized by methoxy polyethylene glycol (MPEG) and methyl acrylic acid (MAA). Lv et al. Synthesized a new kind of PCE by introducing citric acid to the polycarboxylic molecule as a branch to solve concrete’s slump loss, bleeding, and segregation. Excellent PCE was obtained when n(PEGAA): n(PEGCM): n(MA): n(AA): n(SAS) = 1: 0.1 : 0.3: 0.2: 0.05, the initiator was 0.8% (NH4)2SO4 by mass of vinyl monomers, the reaction time was 2-3 h, and the reaction temperature was 80°C. It was shown in the application result that the water-reducing ratio of the product reached 32%, retardation time extended by five h, and concrete with PCE had excellent slump retention, without segregations, and with high compressive strength. A two-step process completed direct polymerization to obtain PCE, which could get unique products with high purity. However, it was also considered to cost more due to its complexity.

Functional Polycarboxylate superplasticizer monomer

Ferrari et al. Synthesized a series of PCEs depending on the branch length, density, and molecular weight and did some tests. The results showed that fractions of higher molar weight were adsorbed to a more significant extent than fractions of lower molecular weight. Yang used azobisisobutylamidine hydrochloride (AIBA·2HCl) as an initiator in polymerization of polyoxyethylene allyl ether (APEG) and maleic anhydride (MA) to synthesize PCE-1. Also, Isoamyl enol polyoxyethylene ether (TPEG), the activity of acrylic acid (AA), and methacrylic sulfonate (MAS) were used to synthesize PCE-2. The results showed that when mixing PCE with concrete, the slump-retaining ability and the performance of late compressive strength of concrete enhancement were better than the similar PCE initiated by ammonium persulfate (APS). Yuused allyl alcohol polyoxyethylene (APEG), acrylic acid (AA), maleic anhydride (MAD), and sodium methyl acrylamide (SMAS) as primary raw materials to gain PCE. The compatibility between PCE and cement was excellent. The configuration concrete had excellent characteristics, such as lower slump loss. The water-reducing ratio in concrete was 32.4% at the solid dosage of 0.3%. Du used maleic anhydride, methyl methacrylate sulfonic acid sodium, allyl base polyethylene glycol (PEG) as raw materials, and ammonium persulfate as initiator. He synthesized poly Malay PCE, according to the cement paste slurry flow degree tests to determine the best synthetic process conditions for the poly Malay PCE: maleic anhydride, PEG, and methyl methacrylate sulfonic acid sodium with the best molar ratio 4 : 1: 0.2. PEG with a molecular weight of 2400 was selected, the initiator was added in two portions, and the polymerization was carried out at 80°C for 5 hours. Hu researched the influences of a single factor in synthesis, confirming the optimal ratio of raw materials, testing the performance of PCE, and characterizing the molecular structure. It was indicated in test results that the expected functional group was introduced into the system. According to the measured data of GPC, the Mw, Wn, MCL, and SCL of APEG and TPEG type PCE were followed by 14700 g/mol, 103000 g/mol, 7540 g/mol, and 84500 g/mol, 2.5 nm and 1.8 nm, and 15.3 nm and 15.3 nm.

Price of Polycarboxylate superplasticizer monomer

Polycarboxylate superplasticizer monomer particle size and purity will affect the product's Price, and the purchase volume can also affect the cost of Polycarboxylate superplasticizer monomer. A large amount of large amount will be lower. The Price of Polycarboxylate superplasticizer monomer is on our company's official website.

Polycarboxylate superplasticizer monomer supplier

If you are looking for high-quality Polycarboxylate superplasticizer monomer, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com). We accept payment via Credit Card, T/T, West Union, and Paypal. TRUNNANO will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.

What Polycarboxylate superplasticizer monomer

Nowadays, many efforts have been made to improve the structure and the synthesis of PCEs. Plank synthesized polycarboxylates using acrylic acid and isoprenyloxy polyethylene glycol (IPEG) at 60°C. The results showed that PCE with optimal dispersing effectiveness was achieved at high contents of IPEG, a molecular weight (Mw) around 40000, and narrow molecular weight distribution in another study by Liu et al. Amide-structural polycarboxylate superplasticizers (amide-PCEs) were produced by amidation reaction between polyacrylic acid (PAA) and amino-terminated methoxy polyethylene glycol (amino-PEG) at 130–150°C. Yu et al. Used butenyl alkylene polyoxyethylene-polyoxypropylene ether (BAPP) as macromonomers and 2, 2-azoisobutyronitrile as an initiator in N2 atmosphere for 48 h at 70°C. They tended to synthesize a polycarboxylate that could significantly accelerate cement hydration. In Lange’s study [10], acrylic acid and ω-methoxy poly (ethylene glycol) methacrylate ester were used to synthesize nonadsorbing polycarboxylates at 80°C within four hours. It was found that all the synthesized polycarboxylates, which did not adsorb on cement, could enhance dispersion and flowability significantly. Researchers developed excellent PCE with higher water reduction, good adaptability, and other good performances. At the same time, they have been trying to broaden sources of raw materials and synthetic processes, reduce the cost of production, and improve the quality of stability step by step. So, the purpose of this study was to discover 

their development trends by reviewing the synthesis progress of polycarboxylate, hoping to help the development of this industry.

Direct Polycarboxylate superplasticizer monomer

Huang chose different monomers, the ratio of various monomers, and adjusted the reaction process. A series of PCE was synthesized with allyl alcohol polyethylene glycol (APEG, EO = 45), acrylic acid (AA), maleic anhydride (MAL), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), and ammonium persulfate (APS) as well. To determine the optimum process of PCE, various reaction conditions for PCE were intensively investigated, such as reactant concentration, temperature, and the molecular ratios of monomers. Sun and Lei synthesized PCE based on aqueous solution polymerization by methyl acrylic acid (MAA), methoxy polyethylene glycol methacrylate (MPEGMA), and sodium methyl acryl sulfonate (SMAS). There were optimum reaction conditions he considered as follows: the ratio of n(MA): n(AA): n(XPEG) was 2 : 2: 1, the amount of initiator was 1.5%, the reaction temperature was 70°C, and the reaction time was six h. Ran et al. Synthesized two different groups of comb-like copolymer dispersants with side chain lengths ranging from 8 to 48 by direct polymerization. Plank et al. Synthesized a new kind of methacrylate polycarboxylate with polyoxyethylene side chain hydroxyl groups at its terminal in side chains, which was different from the traditional one with methoxy side chains. It was shown that there was a comb structure in copolymer, which had good adaptability in cement. Also, it had good application prospects. Yamada et al. Analyzed the characteristics of PEO’s side chain length and degree of polymerization. It was shown that the effects of chemical structure on the paste fluidity were not significant at high w/c. Zhu et al. Synthesized PCE in the water solution by using allyl alcohol polyoxyethylene (APEG), methacrylic acid (MAA), maleic anhydride (MA), and sodium methacrylic sulfonate (MAS) as monomers and the ammonium persulfate as initiator. The optimal synthesis conditions were determined as follows: n(MA): n(MAA): n(APEG): n(MAS) = 215: 310 : 110: 0.5, the initiator dosage was 5% of the monomer weight, and the reaction time was 4-5 h. It was considered that a certain proportion of the anionic polar groups (such as –COOH and −SO3H) were introduced into main chains in PCE. Thus, hydrophilic leading chains were generated, which had strong hydrogen bonds in water. They could form a stable three-dimensional hydrophilic protective layer and provide steric hindrance. By adjusting the proportion of each functional group of the polymer’s leading chains and side chains, the structural balance was achieved to improve water reduction..

Functional Polycarboxylate superplasticizer monomer

Functional polymerization was a modification based on the original polymer. The usual practice was to esterify and graft polyether into leading chains at high temperatures. Sun et al.Grafted alkoxyamine as a reactant with PCE in 10–20% of –COOH mole. The mixture lasted at 150°C for 1.5–3 h, and then some catalyst was added. The mixture was cooled at 100–130°C, and the desired product was obtained. Wang and Feng used some proportion of MAS, water, and ammonium persulfate in a three-necked flask equipped with a condenser and stirrer and heated them to 80°C to gain yellow liquid after 3.5 h. Then, he mixed polyethylene glycol monomethyl ether and dimethyl sulfoxide at 110°C, and the reaction mixture was refluxed five h, and a new kind of PCE whose solid content was about 30% was obtained. Peaks of −OH, −SO3H, −C=O, and C-O could be found obviously in FTIR. When the molar ratio of carboxyl, sulfonic acid, and polyoxyethylene in side chains was 0.542 : 0.354: 0.104, the best performance would be gained in graft copolymer.

Price of Polycarboxylate superplasticizer monomer

Polycarboxylate superplasticizer monomer particle size and purity will affect the product's Price, and the purchase volume can also affect the cost of Polycarboxylate superplasticizer monomer. A large amount of large amount will be lower. The Price of Polycarboxylate superplasticizer monomer is on our company's official website.

Polycarboxylate superplasticizer monomer supplier

If you are looking for high-quality Polycarboxylate superplasticizer monomer, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com). We accept payment via Credit Card, T/T, West Union, and Paypal. TRUNNANO will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.

What Polycarboxylate superplasticizer monomer

Polycarboxylate superplasticizers (PCE) provide concrete with high fluidity, strength, and excellent durability at low content, which efficiently promotes the development of the construction industry. The structure of PCEs, such as functional groups, monomer sequence, molecular weight property, length of main chain, and side chain density, directly affect the fluidity of cement paste. The long main chain length of PCE provides a polymer with enough adsorption groups onto the cement particles. In contrast, the high density of the side chain provides a substantial hindrance steric between the surface of cement particles. The optimal PCE requires the content and arrangement equilibrium of anchor and steric hindrance groups, which are exhibited as a monomer sequence along the backbone. PCE polymers with high feeding ratios of unsaturated carboxylic acid and macromonomer own higher ratio of AAA and monomer sequences (A represented acrylic acid, E represented isoprenyl oxy polyethylene glycol ether) [9] in PCE polymers. The influence of molecular structures of PCE on the fluidity and hydration process of cement paste has always been the research hotspot. The high content of unsaturated carboxylic acid may lead to the hydration delay of cement paste. Conversely, it provides high charge density and adsorption driving force for PCE polymers. Meanwhile, high side chain density should be guaranteed to supply PCE polymers with steric solid hindrance. The kinetic chain presented in Formula (1) is a decisive factor of molecular weight for polymers in aqueous free radical polymerization, and it is directly proportional to the monomer concentration [M] but inversely proportional to the square root of initiator concentration [I]. The kinetic chain length varies with the monomer concentration [M] exclusively under the fixed initiator concentration and reaction temperature. Here, kd and kt are designated as chain initiation rate constant, chain propagation rate constant, and chain termination rate constant, respectively.

Influence of Monomer Ratios on Molecular WeightProperties

There was no apparent split and narrow molecular weight distribution for the final product 52IPEG series PCE polymers in the SEC spectra with A/Eamong 3.0 and 6.0 exhibited in Figure 1. The SEC ranges of 52IPEG4.2, 52IPEG5.0, and 52IPEG6.0 PCE samples were similar. The mass fraction of residual macromonomer in 52IPEG3.0 was much higher than in other models. There were two reasons for the low conversion of 52IPEG macromonomer in 52IPEG3.0: firstly, the macromonomer inclines to copolymerization rather than homopolymerization, and it cannot be entirely reacted at with a low content of acrylic acid; secondly, the steric solid hindrance effect of EO units decreased the reaction rate on a certain extent. It indicated that the high value of A/E increased the finalconversion of 52IPEG macromonomer. PCE polymers possessed molecular weight of around 30,000 g/mol with low side chain density, and long main chain length presented high initial dispersing effectiveness at the low dosage-around 0.12%. Most effective PCE polymers were formed during the adding period of acrylic acid in the first three h. The structures of PCE polymers synthesized at the A/Evalue of 3.0, 4.2, 5.0, and 6.0 were studied. The molecular weight, main chain length, and reaction rate of PCE polymers, as well as the conversion of macromonomers, increased with the general adding ratio of acrylic acid to 52IPEG macromonomers. Polymers with a mass fraction of 53.8% were detected in 52IPEG6.0 after one h, and it was even higher than that of polymers of 52IPEG3.0 produced in the first two h.

Dispersing Effectiveness inPolycarboxylate Superplasticizers

The side chain density of polymers decreased with the general A/Evalue during the reaction process in a specific PCE sample. The continuous feeding of AA during the reaction was the reason that lowered the side chain density of polymers. PCE polymers produced in the 1st hour possessed the highest side chain density and molecular weight. It was the critical period for the structure control of PCE polymers, especially for high A/Evalue ones. The major effective polymers were produced by adding acrylic acid in the first three h. A high dosage of 0.26% for 52IPEG3.0 was needed to reach the initial cement paste flowspread of 26±0.5 cm, yet it exhibited excellent retention ability. Around 0.12% of dosages were required for other PCE polymers, but their retention properties were not good. 52IPEG4.2 possessed a molecular weight of about 30,000 g/mol and moderate side chain density; the main chain length 1 was the proper choice for the application. The structure of PCE polymers with specific properties could be designed based on influence factors.

Price of Polycarboxylate superplasticizer monomer

Polycarboxylate superplasticizer monomer particle size and purity will affect the product's Price, and the purchase volume can also affect the cost of Polycarboxylate superplasticizer monomer. A large amount of large amount will be lower. The Price of Polycarboxylate superplasticizer monomer is on our company's official website.

Polycarboxylate superplasticizer monomer supplier

If you are looking for high-quality Polycarboxylate superplasticizer monomer, please feel free to contact us and send an inquiry. (sales@cabr-concrete.com). We accept payment via Credit Card, T/T, West Union, and Paypal. TRUNNANO will ship the goods to customers overseas through FedEx, DHL, by air, or by sea.