# Analysis and Modelling of Shrinkage and Creep of Reactive Powder Concrete
## 1 Introduction  
Reactive powder concrete (RPC) is a type of ultra-high performance concrete which has been developed in the last two decades [1; 2]. RPC has superior compressive and tensile strengths, which can significantly reduce the dead load of structures [3; 4]. Thus, it is especially suitable for long-span bridge decks, thin-plate structures, and field-cast joints for precast bridge decks [5]. It possesses superior energy absorption owing to the addition of steel fibre [6], provides good structural reliability, and has excellent durability, leading to a long service life. It is also almost impermeable, which almost entirely prevents carbonation and penetration of chlorides and sulphates, thereby making it suitable for use in harsh climatic conditions such as freeze-thaw or coastal areas [7]. However, the high cement content (usually as high as 800-1000 kg/m\({}^{3}\)) affects production costs and increases the risk of shrinkage [8; 9; 10; 11; 12]. Furthermore, the addition of silica tune increases the risk of shrinkage and creep of RPC [13; 14; 15; 16]. Shrinkage and creep can significantly affect the long-term characteristics of concrete. In large scale structures, shrinkage and creep can increase the width of cracks and structural deformation. It can also cause stress loss in the prestressed reinforcement of prestressed components [17]. Therefore, it is important to predict and monitor the shrinkage and creep of concrete. In recent years, many studies on the shrinkage and creep of normal strength concrete have been carried out, and mature theoriesand models have been developed [18; 19; 20]. However, there are relatively few studies on the shrinkage and creep of RPC. To produce RPC, it is necessary to minimize the aggregate size, increase the paste/aggregate ratio, decrease the water/binder ratio, add silica fume and steel fibre, and use steam-heat curing. All these measures make the shrinkage and creep characteristics of RPC different from those of normal strength concrete. [PERSON] et al. investigated the autogenous shrinkage of steam-heat cured RPC [21], and the results showed that three factors (i.e., steel fibre, silica fume, and aggregate size) have significant effects on the autogenous shrinkage of RPC. Furthermore, the autogenous shrinkage mainly occurred during the stream-heat curing period. [PERSON] et al. studied the effects of different supplementary cementitious materials (i.e., silica fume, fly ash, and ground granulated blast furnace slag) on the autogenous shrinkage of RPC, and developed an autogenous shrinkage model for RPC [16]. [PERSON] et al. conducted studies on the shrinkage of RPC with water curing for 3 days, and observed that the shrinkage increases with increasing water/binder ratio, cement content, and silica fume content [22]. [PERSON] found that adding rice husk ash to RPC can reduce the autogenous shrinkage of RPC significantly [23]. Moreover, several other measures such as using expansive additives, shrinkage reducing admixtures, or coarser cement particles, and improving curing conditions were identified to decrease the autogenous shrinkage of RPC [24; 25; 26; 27]. [PERSON] et al. demonstrated that both the autogenous and drying shrinkage of RPC increase with raising granulated blast furnace slag (GBFS) [28]. [PERSON] et al. studied the dry shrinkage of RPC with water curing for 28 days, and found drying shrinkage increases with increasing water/binder ratio and superplasticizer dosage [6]. [PERSON] suggested that adding coarse aggregate to RPC can reduce its drying shrinkage and creep [29]. [PERSON] found that high compressive stress (axial stress of higher than 0.60) on relatively low strength RPC cause significant short-term creep [30]. To the best of the authors' knowledge, previous studies on the shrinkage and creep of RPC have mainly focused on the autogenous shrinkage of RPC. The effects of RPC components on autogenous shrinkage have been investigated. In addition, some measures have been purposed to decrease the autogenous shrinkage of RPC.