*2.1. Materials*

The cement is P·O 42.5 ordinary Portland cement produced by Jinyu Group. Its basic performance is shown in Table 1, in accordance with the requirements of Chinese standard GB/T 175. The specific surface area and the chemical composition of PS and LS are shown in Table 2. The reaction formula of PS is shown as in Equation (1). The size of coarse aggregate is 5–25 mm, and other indexes meet the requirements of Chinese standard GB/T 14685. The fine aggregate is river sand, and the fineness modulus is 2.4. The water is tap water.

$$2\text{Ca}\_3(\text{PO}\_4)\_2 + 10\text{C} + 6\text{SiO}\_2 \rightarrow \text{P}\_4 + 10\text{CO} + 6(\text{CaO} \cdot \text{SiO}\_2) \tag{1}$$


**Table 1.** Properties of cement.


**Table 2.** Chemical composition and specific surface area of phosphorus slag and limestone powder.

### *2.2. Sample Preparation*

Table 3 shows the mix proportion of concrete with different content of PLC. The pure cement was taken as the control sample, and the mass ratio of PS to LS was 1:1. L-1 was using PLC to replace 20% of pure cement and the water/binder ratio was 0.425. L-11 was using PLC to replace 20% of pure cement, but the water/binder ratio was 0.418. The total amount of L-2 cementitious materials was 420 kg/m<sup>3</sup> . PLC accounted for 33% of the total cementitious materials, and the water/binder ratio was 0.405. Meanwhile, the water cement ratio of L-22 was reduced to 0.39 with the same content of PLC. The workability of concrete was adjusted by a water reducing agent to keep consistent slump. The effects of the content of PLC and water/binder ratio on the mechanical properties, shrinkage and durability of concrete were studied.

**Table 3.** Mix proportion of concrete mixed with phosphorus slag powder and limestone powder (unit kg/m<sup>3</sup> ).

