The first generation is generally manufactured from lignosulfonates and is usually called the ordinary water-reducing agent. The second one is made from sulfonated naphthalene formaldehyde or sulfonated melamine formaldehyde which belongs to the superplasticizer.
In the field of building materials, research about cellulose derivatives such as water-reducing agent has also been attracted the attention and it has been reported that the main raw materials for the preparation of the water-reducing agent is based on biomass including cellulose, hemicelluloses, and starch and the modification methods including carboxymethylated, carboxyethyl, alkyl sulfonic acid, and sulfuric acid esterification.
According to current reports, the raw materials used for the production of the water-reducing agent are mostly cellulose products.
In this paper, wheat straw waste was joined in the preparation of polycarboxylate superplasticizer (PCS), through the graft copolymerization of the large molecules of straw fiber and PCS to improve the performance of the water-reducing agent as well as to reduce its production cost.
To achieve good strength gain, especially at an early age, the unit water content was controlled to be less than 150 kg/[m.sup.3], and a polycarboxylate-based water-reducing agent was added after being specially modified through the adjustment of the amount of polyethylene glycol alkyl ether and the addition of an amine.
To maintain good workability of the concrete at lower unit water content, the molecular structure of a polycarboxylate-based water-reducing agent was specially modified as follows.
To meet the designed initial air content ([A.sub.c]) and slump ([S.sub.i]), an air entraining agent and the specially modified polycarboxylate-based high-range water-reducing agent were added, as given in Table 4.
"The lignin-based water-reducing agent
had, in general, a higher air-entraining effect than the superplasticizer when used in combination with air entrainers.
* 56.5 49.6 176 312 860 882 3.12 * Air entraining water-reducing agent
According to Figure 4 (the icon being early-strength water-reducing agent
), under fixed water-cement ratio and invariable amount of early-strength water-reducing agent
, the final volume of material 1 increases with the amount of fiber expansive agent.
The attention is paid to optimizing the preparation conditions of graft copolymerization of the large cellulose molecules of straw fibre and superplasticizer to improve the performance of the water-reducing agent
as well as to reduce its production cost.
prepare a novel binary modified maltodextrin as a water-reducing agent