Method for compression casting concrete by reducing cement

Abstract

The present disclosure discloses a method for compression casting concrete by reducing an amount of cement, including: adopting any existing concrete mix proportion designed for concrete of given strength, mixing the concrete, pouring the concrete into a mould, and compressing the concrete at a given pressure, where 28-day strength of the compacted concrete is increased; gradually reducing an amount of cement while keeping amounts of other materials unchanged, where 28-day strength of the concrete is gradually reduced until the concrete meets a design index; proportionally reducing amounts of water and cement in a last mix proportion while keeping amounts of other materials unchanged, where during compression casting of the concrete, discharge of cement paste is gradually reduced until no cement paste is discharged; and compression casting a concrete member according to a final mix proportion.

What is claimed is: 
     
         1 . A method for compression casting concrete by reducing an amount of cement, comprising the following steps:
 mixing concrete raw materials according to any existing concrete mix proportion designed for specific concrete performance;   pouring concrete obtained by the mixing into a mould, and compressing the concrete in the mould using a compression device at a set pressure, such that the concrete is compacted and excess cement paste is extruded;   gradually reducing an amount of cement in the concrete mix proportion while keeping amounts of other materials unchanged since performance of the compression cast concrete exceeds an original performance index, and obtaining a new mix proportion each time the amount of cement is reduced; and de-moulding compression cast concrete obtained at each new mix proportion and curing for 28 days, and carrying out a compressive strength axial compression test to evaluate a relationship between cement reduction and strength, wherein 28-day strength of compression cast concrete obtained at the new mix proportion is gradually reduced until performance of the concrete is reduced to meet a design index;   proportionally reducing amounts of water and cement in a last mix proportion while keeping amounts of other materials unchanged, and compressing and casting concrete of a new formula obtained each time the amounts of water and cement in the mix proportion are reduced, wherein during compression of the concrete of the new formula, discharge of cement paste is gradually reduced until there is no cement slurry, or only a small amount of cement paste is discharged after the compression; and at this time, the amount of cement is a minimum amount of cement in formulas of the compression cast concrete meeting a performance index, and a mix proportion is used as a final mix proportion of the compression cast concrete; and   compression casting a concrete member according to the final mix proportion.   
     
     
         2 . The method for compression casting concrete by reducing an amount of cement according to  claim 1 , comprising the following step before the step of mixing concrete raw materials according to any existing concrete mix proportion designed for specific concrete performance:
 selecting and preparing the concrete raw materials required for concrete preparation.   
     
     
         3 . The method for compression casting concrete by reducing an amount of cement according to  claim 1 , wherein the concrete raw materials comprise, but are not limited to, the water, the cement, coarse aggregates, and fine aggregates. 
     
     
         4 . The method for compression casting concrete by reducing an amount of cement according to  claim 1 , further comprising the following steps after the step of pouring concrete obtained by the mixing into a mould:
 vibrating the concrete in the mould with an insert type vibrator to make the vibrated concrete reach a preset height in the mould; and   aligning and leveling the mould and the compression device.   
     
     
         5 . The method for compression casting concrete by reducing an amount of cement according to  claim 4 , further comprising the following step before the step of compressing the concrete in the mould using a compression device at a set pressure: setting compression parameters. 
     
     
         6 . The method for compression casting concrete by reducing an amount of cement according to  claim 5 , wherein the compression parameters comprise the set pressure and compression time. 
     
     
         7 . The method for compression casting concrete by reducing an amount of cement according to  claim 3 , wherein a process of gradually reducing an amount of cement in the concrete mix proportion while keeping amounts of other materials unchanged specifically comprises:
 reducing the amount of the cement in the initial given mix proportion while keeping the amounts of the water, the coarse aggregates, and the fine aggregates unchanged.   
     
     
         8 . The method for compression casting concrete by reducing an amount of cement according to  claim 7 , wherein a process of proportionally reducing amounts of water and cement in a last mix proportion while keeping amounts of other materials unchanged specifically comprises:
 reducing the amounts of the cement and the water in the mix proportion while keeping the amounts of the coarse aggregates and the fine aggregates unchanged.   
     
     
         9 . The method for compression casting concrete by reducing an amount of cement according to  claim 6 , wherein the set pressure is greater than or equal to 5 MPa. 
     
     
         10 . The method for compression casting concrete by reducing an amount of cement according to  claim 6 , wherein the compression time is greater than 2 minutes.