Performance and Mechanism of a Multi-Functional Superplasticizer for Concrete

Abstract

Shrinkage reducing admixtures (SRA) have been used for several years to reduce the shrinkage of concrete. However, because their prices are very expensive and their dosages are very large, it is not economical for their practical application. Another problem of SRA is the degradation of compressive strength of concrete with SRA. In order to solve the two problems, a new polycarboxylate based superplasticizer with shrinkage reducing function was developed and its mechanism was investigated. According to experimental results, the admixture named JM-PCA (IV) reduces shrinkage of concrete effectively and reduces water content effectively. JM-PCA (IV) at a dosage of 0.25% decreases the shrinkage of concrete by about 40 to 55 percent at 28 days and 60 days when compared with sulfonated naphthalene formaldehyde condensate superplasticizer at a dosage 0.74%. The possible reason is that a shrinkage reducing component (SRC) and long ethylene oxides(EO) side chain were introduced into the molecular structure. The adsorption-reduction of interface tension is thought to be its main action mechanism of the reduction of shrinkage of

Synthesis of a Novel Polycarboxylate Superplasticizer with Hyperbranched Structure

“…Traditional PCE polymers are composed of polyethylene main chain, poly (ethylene glycol) branch chain and carboxylic side groups, and it's convenient to achieve diverse functions and specially solve some problems in concrete engineering because their chemical structure has the potential to be modified . As an important type of concrete admixture, the main function of superplasticizers is to increase the dispersion of cement paste,, leading to a low water‐to‐cement ratio (w/c) and high strength concrete. Compared with other water reducing agents, PCE exhibits excellent water‐reducing performance, outstanding slump retention ability, low dosage and wide range of adaptability .…”

Production of Flocculants, Adsorbents, and Dispersants from Lignin

“…This is because sulfonate anions have more hydrophilic affinity than carboxylate anions [ 110 ]. However, common dispersants used in cement admixtures, such as sulfonated melamin-formaldehyde and sulfonated naphthalene-formaldehyde, have the disadvantages of enhanced concrete shrinkage, meager dispersibility, and pollution [ 113 , 114 ].…”

Effect of the length of the side chains of comb-like copolymer dispersants on dispersion and rheological properties of concentrated cement suspensions

“…Recently, comb-like copolymers with grafted polyethylene oxide pendant groups have been widely used as polymeric cement dispersants, also known as superplasticizers in the concrete industry due to their unique properties compared to traditional polyelectrolyte dispersants, such as outstanding water reducing ratio, high workability retention at small dosages, and excellent compatibility with higher dosage rates of industrial by-products [1][2][3][4]. These type of polymers have also proven to be effective robust dispersants for many complex ceramic systems [5][6][7].…”