# One-Dimensional Modeling of the Pressure Loss in Concrete Pumping and Experimental Verification
## 1 Introduction
[18] found that the pumping concrete resistance in the conveying process consists of adhesion and friction, the adhesion coefficient and velocity coefficient are mainly affected by the slump of the concrete, and the formula for the pumping pressure loss can be deduced according to the force balance. [PERSON] et al. [19] considered the thickness of the lubrication layer and deduced equations for calculating the flow rate and pressure loss. [PERSON] et al. [20] established a pipeline direction-finding pressure model by considering the influence of viscous loss and combining [PERSON]'s equation. These experimental and modeling results provide insights for the analysis of coarse aggregates in pumping rheological properties. Coarse aggregate particles' shape [21] and distribution characteristics [22] affect the rheological properties of concrete, which directly affect the pumping pressure loss [23]. [PERSON] et al. [24] used three different coarse aggregate sizes to run the 170 m and 1000 m pumping circuit tests to measure the pumping pressure at the same flow rates, and the results showed a linear relationship between the pumping pressure and flow rate. [PERSON] et al. [25] used the degree of sphericity and shape index to characterize the shape of coarse aggregate particles, researched the influence of its shape on the flowability of concrete, and found that as the shape index and the degree of sphericity increased, the concrete became less viscous and better liquidity. [PERSON] et al. [26] studied the influence of the coarse aggregate volume fraction on the concrete pumping pressure based on the discrete element method. The results showed that the topography characteristics of the lubricating layer and coarse aggregate in the pipe have a great influence on the pumping pressure loss. However, few researchers have considered the effect of coarse aggregate particles on the blocking effect of mortar in the lubricating layer. Because the aggregate particle size is larger than the lubrication layer thickness, the blocking effect of the aggregate particles increases the vortices in the lubrication layer. The exposed aggregate particles in the lubrication layer are considered multiple localized obstructions. These obstructions will affect the distribution of the mortar flow pattern in the lubrication layer and the concrete pumping pressure loss. According to the above discussion, the focus of this paper is to study the pressure loss caused by the blocking effect of coarse aggregate. The flow characteristics of the pumping concrete lubrication layer and plunger layer are combined with the concrete coarse aggregate particle distribution characteristics. The aggregate particle blocking effect is converted into the wall roughness by means of the aggregate particle equivalent size. [PERSON]'s equation is used to construct a one-dimensional flow model for the concrete pumping pressure loss, and expressions for pressure loss calculations are derived via [PERSON]'s and [PERSON]'s formulas. A project pumping pipeline is taken as a research object, strain electrical measurement technology is used to measure the pressure of the pumping pipeline, and the calculation accuracy of the equivalent one-dimensional flow model is tested and analyzed.