CN105804321B - Steel pipe gypsum mortar discarded concrete coupled column and preparation method thereof - Google Patents

Abstract

The invention discloses a steel pipe gypsum mortar waste concrete composite column, which is characterized in that it comprises a steel pipe, gypsum mortar and waste concrete blocks filled in the steel pipe, both ends of the steel pipe are sealed by end plates, A plurality of vibrating holes are arranged, and a plurality of longitudinal steel bars are evenly distributed on the inner wall of the steel pipe. The invention also discloses a method for preparing the steel pipe gypsum mortar waste concrete composite column. The steel pipe gypsum mortar waste concrete composite column prepared by the invention has the characteristics of fast hardening and early strength, and can quickly reach the bearing capacity; and the strength of the component is mainly provided by the skeleton of the waste retarded soil block, which can reduce the material cost; in addition, the gypsum mortar is only used Used as cementitious material and caulking material, there are external constraints of steel pipes, which can weaken the weak interface between gypsum mortar and waste concrete blocks, and greatly improve the strength and ductility of components.

Description

Steel pipe gypsum mortar waste concrete composite column and preparation method thereof

technical field

The invention relates to a steel pipe gypsum mortar waste concrete composite column and a preparation method thereof.

Background technique

With the rapid development of the construction industry, the demolition, reconstruction and repair of villages and towns, the continuous development and large-scale construction of new urban areas and residential quarters, and the new construction of municipal public facilities will generate a large amount of construction waste. In addition, some building structures in our country are about to reach the design service life. According to statistics, my country's annual demolition projects account for 40% of the total construction projects, and every 10,000 square meters of demolition projects will generate 7,000-12,000 tons of construction waste. Using crushed construction waste as recycled aggregate can not only solve the shortage of natural aggregate resources, realize the regeneration and recycling of concrete, and ensure the sustainable development of the construction industry. A large number of experimental studies have been done on the performance of recycled concrete at home and abroad, showing that recycled concrete has good performance and can be used in actual engineering construction. The current waste concrete composite columns are generally filled with waste concrete blocks, cement, coal ash and other materials in steel pipes. This kind of composite columns has disadvantages such as slow setting speed and poor early strength, and the bonding strength between filling materials and steel pipes is poor. .

Contents of the invention

In view of the lack of background technology, the technical problem to be solved by the present invention is to provide a steel pipe gypsum mortar waste concrete composite column with rapid hardening, early strength, good ductility and low cost and its preparation method.

For this reason, the present invention adopts following technical scheme to realize:

A steel pipe gypsum mortar waste concrete composite column comprises steel pipes, gypsum mortar and waste concrete blocks filled in the steel pipes, and the two ends of the steel pipes are sealed by end plates.

The gypsum mortar consists of water, gypsum and sand.

A setting retarder is also added to the gypsum mortar.

The maximum diameter of the waste concrete block is 1/4-1/3 of the diameter of the steel pipe, and the minimum diameter of the waste concrete block is 20-30mm.

The ratio of water, gypsum and sand is 0.3:1:1-0.5:1:1.

The retarder is citric acid.

The present invention also provides a method for preparing the above-mentioned steel pipe gypsum mortar waste concrete composite column, comprising the following steps:

(1) Weld the bottom of the steel pipe with an end plate to seal it, then fill the steel pipe with gypsum mortar with a thickness between 1/2-1 of the steel pipe diameter, and add a certain amount of retarder to the gypsum mortar as needed to adjust Flocculation time of gypsum mortar;

(2) Alternately throwing waste concrete blocks and/or crushed stones and/or pebbles and filling gypsum mortar into the steel pipe;

(3) After the gypsum mortar is set, weld the end plate on the top of the steel pipe.

After adopting the above technical scheme, the strength of the composite column is mainly provided by waste concrete blocks, and the gypsum mortar is only used as cementing material and joint filling material. The gypsum mortar can be formed in 20-30 minutes after pouring, and its strength can reach 20-60MPa. It has the characteristics of rapid hardening and early strength, and the strength of the component is mainly provided by the skeleton of the waste retarded concrete block. The gypsum mortar is only used as a cementing material and a joint filling material, and there are steel pipes outside, which can weaken the gypsum mortar and waste concrete. The determination of the weak interface between the blocks can not only greatly improve the strength and ductility of the component, but also reduce the material cost.

Description of drawings

The present invention has following accompanying drawing:

Fig. 1 is a schematic structural view of a steel pipe gypsum mortar waste concrete composite column provided by the present invention.

Detailed ways

Referring to Fig. 1, the steel pipe gypsum mortar waste concrete composite column provided by the present invention comprises steel pipe 1, gypsum mortar 2 and waste concrete blocks 3 filled in the steel pipe 1, the two ends of the steel pipe 1 are sealed by end plates, and the gypsum mortar 2 is filled with water , gypsum and sand, the ratio of water, gypsum and sand is 0.3:1:1-0.5:1:1, the greater the amount of mixing water, the lower the strength, the better the fluidity, and the gypsum mortar 2 is also added with retarding The retarder is citric acid, which is used to adjust the flocculation time of the gypsum mortar 2. The maximum diameter of the waste concrete block 3 is 1/4-1/3 of the diameter of the steel pipe 1, and the minimum diameter of the waste concrete block 3 is 20-30mm .

Referring to Fig. 1, in order to increase the structural strength, there are many pairs of transverse reinforcing bar sockets 4 arranged along the height direction on the side wall of the steel pipe, and the transverse reinforcing bars 5 pass through the steel pipe 1 and both ends are inserted into the transverse reinforcing bar sockets 4. The transverse steel bar 5 is welded and fixed to the steel pipe 1 wall. In view of the large volume of the waste concrete block 3, it is impossible to obtain enough bearing space in the steel pipe 1 if the usual reinforcement cage structure is adopted, so the structure in which the horizontal reinforcement 5 is inserted into the horizontal reinforcement insertion hole 4 helps to integrate the reinforcement with the composite column Core bonded for strength.

The present invention also provides a method for preparing a steel pipe gypsum mortar waste concrete composite column, comprising the following steps:

(1) Weld an end plate at the bottom of the steel pipe 1 for sealing, then fill the steel pipe with gypsum mortar 2 with a thickness between 1/2-1 of the diameter of the steel pipe, and add a certain amount of retarder to the gypsum mortar 2 as required, Used to adjust the flocculation time of gypsum mortar 2;

(2) Alternately throwing waste concrete blocks 3 and/or crushed stones and/or pebbles and filling gypsum mortar into the steel pipe;

(3) After the gypsum mortar 2 is set, weld the end plate on the top of the steel pipe 1.

In the above step (2), when throwing waste concrete blocks 3 and/or crushed stones and/or pebbles and filling gypsum mortar into the steel pipe 1, every time a pair of transverse reinforcement insertion holes 4 are reached, the horizontal reinforcement insertion holes 4, insert the transverse reinforcement 5, and weld the transverse reinforcement 5 on the steel pipe 1 wall from the outside of the steel pipe 1. The insertion method of the transverse reinforcement provided in this embodiment can avoid the contact between the transverse reinforcement 5 and the large-volume aggregates such as the waste concrete block 3, avoid affecting the loading of large-volume aggregates, and at the same time improve the overall strength of the composite column.

Claims (2)

1. A steel pipe gypsum mortar waste concrete composite column is characterized in that: it comprises a steel pipe and gypsum mortar and waste concrete blocks filled in the steel pipe, the two ends of the steel pipe are sealed by end plates; the gypsum mortar is composed of water, gypsum and sand composition; the gypsum mortar is also added with a retarder, the retarder is citric acid; the maximum diameter of the waste concrete block is 1/4-1/3 of the diameter of the steel pipe, and the minimum diameter of the waste concrete block is 20-30mm; the ratio of water, gypsum and sand is 0.3:1:1-0.5:1:1; there are many pairs of transverse reinforcement sockets arranged along the height direction on the side wall of the steel pipe, and the transverse reinforcement passes through The two ends of the steel pipe are inserted into the insertion holes of the transverse reinforcement, and the transverse reinforcement is welded and fixed to the wall of the steel pipe. 2. A method for preparing the steel pipe gypsum mortar waste concrete composite column according to claim 1, comprising the following steps: (1) Weld the bottom of the steel pipe with an end plate to seal it, then fill the steel pipe with gypsum mortar with a thickness between 1/2-1 of the steel pipe diameter, and add a certain amount of retarder to the gypsum mortar as needed to adjust Flocculation time of gypsum mortar; (2) Alternately throwing waste concrete blocks and/or crushed stones and/or pebbles and filling gypsum mortar into the steel pipe; throwing waste concrete blocks and/or crushed stones and/or pebbles and filling gypsum mortar into the steel pipe The position where a pair of transverse steel bar sockets are located is to insert the horizontal steel bars into the horizontal steel bar sockets, and weld the horizontal steel bars to the steel pipe wall from the outside of the steel pipe; (3) After the gypsum mortar is set, weld the end plate on the top of the steel pipe.