Evaluations of All-in-One, Polycarboxylate-Based Superplasticizer with Viscosity Modifying Agents for the Application of Normal-Strength, High-Fluidity Concrete  
Tae-Woong Kong  
1R&D Center, Sunil Industrial Co., LTD, 68, Gwilin-ro, Dongan-gu, Anyang-si 14080, Korea: [EMAIL_ADDRESS]  
[PERSON]  
2 Innovative Durable Building and Infrastructure Research Center, Haryang University, 1271 Sa 3-dong, Sangrook-gu, Ansan-si 15588, Korea  
several parameters including particle and fluid movement. The stability of concrete can be classified into the separation and sedimentation of coarse aggregate and cement paste in concrete, as well as the bleeding of concrete [11; 12; 13]. In particular, to produce normal strength concrete with a high fluidity and low binder content, the yield stress must be minimized while securing plastic viscosity [14; 15; 16]. For this, the filling ability with the high dispersion effect of the superplasticizer should be utilized [17; 18]. However, there was a limitation in ensuring the high workability, strength, and durability of conventional, polycarboxylate-based superplasticizer concrete with a normal strength and a low amount of binder.  
These problems can be solved by adding VMA and PCE to help improve the fluidity of the concrete by the improved filling and dispersion ability of the binders [19; 20]. In addition, the rheology and stability of the concrete with VMA can be improved by preventing bleeding and segregation problems. VMA improves the retention of cement paste components in the suspension [21], cohesion, stability, and viscosity of the concrete. Therefore, the rheology and stability of the concrete with VMA can be improved by preventing bleeding and segregation problems [22; 23; 24; 25]. Moreover, it can replace mineral admixtures such as fly ash and silica fumes [19].  
Among the most popular VMAs, hydroxypropyl-methylcellulose (HPMC), wlean gum, guar gum, and starch have excellent thickening, adhesive, and water retention properties, and are widely used in construction as an additive to concrete or mortar. HPMC has good adhesive, thickening, and water retention properties, and is mainly applied in self-leveling mortar and self-compacting concrete, with the intention of improving bleeding and aggregate segregation [26; 27]. Welan gum is widely applied to prevent the bleeding and segregation of mortar or concrete, as well as at higher W/C ratios, and less additive is needed [28; 29]. Guar gum improves the water retention of mortar or concrete, adapts the rheological behavior of the cementitious materials, prevents aggregate segregation and improves the workability and homogeneity of cement-based systems. Moreover, the addition of the guar gum slightly increases the strength and reduces the carbonation rate [30; 31]. Starches are VMA that alter the properties of a mortar in the fresh state. They improve the viscosity and homogeneity of a material in mortars and concretes, and are often used together with a high-range, water-reducing admixture to avoid segregation and bleeding and to improve the cohesion of a mortar or concrete [22; 24].  
Despite the many advantages of VMA in concrete or mortar, if PCE and VMA are mixed and stored, then there is issue of productivity, usability, and storage in ready-mixed concrete plants [32].  
The above literature search suggests that there are no such studies on the mixing of all-in-one, polycarboxylate-based superplasticizers (NPCE) that did not cause any cohesion or sedimentation even when PCE and VMA were mixed and stored for a long time. Therefore, in the present studies, an all-in-one, polycarboxylate-based superplasticizer, with viscosity modifying agents for the application of normal-strength, high-fluidity con-crete, mixed and evaluated the properties of this concrete.