CN105152591A - Preparation of LC35-grade lightweight aggregate structural concrete - Google Patents

Abstract

The invention discloses a preparation method of LC35 grade lightweight aggregate structure concrete. The main materials of this kind of concrete are cement, sand, ceramsite, fly ash, water and admixture. After mixing ratio and orthogonal test design, the obtained Several proposed mix ratios, and then carry out strength tests according to the mix ratios. The test results and analysis obtained a lightweight aggregate concrete for LC35 structure, which is characterized in that: the dry mass ratio of each component is: cementitious material: sand: ceramsite = 1:1.7:1. The water reducing agent is added according to 1.5% of the cement mass, and the water-binder ratio is 0.36. The prepared light concrete has an apparent density of 1922kg/m ³ . The 28-day compressive strength of the prepared concrete is over 37MPa, meeting the requirements of LC35 lightweight aggregate concrete. This mix ratio can be used as a reference in engineering practice.

Description

Preparation of a kind of LC35 lightweight aggregate structure concrete

technical field

The invention relates to the technical field of application of lightweight aggregate concrete for construction engineering structures, specifically using specific fly ash, slag powder, cement, sand, coarse aggregate, etc., through concrete mix ratio design, orthogonal test design, strength Through testing and optimization, LC35 grade lightweight aggregate concrete meeting the requirements of concrete engineering was obtained.

Background technique

Lightweight structural concrete is one of the development directions of concrete technology in the world at present. Its research and application in structures have just started. There are still many problems to be solved in its application, such as the low strength level of concrete, high cost, concrete mixing The workability of the compound is difficult to meet the construction requirements, so this new material with excellent performance has not been promoted. Strengthening the research on the application of lightweight concrete for structures and promoting the wide application of high-strength lightweight concrete in civil engineering such as high-rise buildings and long-span bridges is conducive to the development of my country's construction industry.

With the rapid development of economy and society, the demand for high-rise buildings has increased greatly, and most high-rise buildings use heavy concrete materials, so that the weight of the building is large, and the structural stress is also large. Concrete material strength is also greater, resulting in higher building costs. The C35 grade concrete is the most used concrete. For this reason, this study explores the development of LC35 lightweight aggregate concrete that can replace C35 ordinary concrete, hoping to apply it in construction engineering. The application of this lightweight concrete reduces the building's own weight, greatly reduces the internal force of the building structure, and improves the construction quality. The anti-seismic performance and the performance of resisting structural thermal stress are beneficial to realize the large span of concrete structure buildings and the construction of super high-rise buildings, reduce the amount of reinforcement, and have certain economic effects. All these have important practical engineering application value.

Contents of the invention

The purpose of the present invention is to adopt C35 concrete consumption to be larger for building structure, and the building structure that adopts this kind of concrete is self-heavy and arrives at the current situation that building bearing capacity and anti-seismic performance are low, has prepared a kind of lightweight concrete that can replace C35, That is, LC35 grade lightweight aggregate concrete. The concrete is light in weight and can greatly reduce the self-weight of the building structure, thereby improving the building's bearing capacity and ability to resist dynamic loads, reducing the amount of steel bars, and improving economy.

In order to achieve the above purpose, a LC35 grade lightweight aggregate concrete with optimized mix ratio was invented, and the main materials used are cement, sand, ceramsite, fly ash, admixture, and water. Through the mix ratio and orthogonal test design, a number of proposed mix ratios are obtained, and then the strength tests are carried out according to the proposed multi-group mix ratios. Through test data analysis and comparison, a kind of lightweight aggregate concrete for LC35 structure is obtained, which is characterized in that: the dry mass ratio of each component is: fly ash: slag powder: cement: sand: ceramsite = 1: 1:4.67:11.32:6.44. The water reducing agent is added according to 1.5% of the cement mass, and the water-binder ratio is 0.36. The prepared light concrete has an apparent density of 1922kg/m ³ . The 28-day compressive strength of the prepared composite concrete is over 37MPa, meeting the requirements of LC35 lightweight aggregate concrete. This mix ratio can be used as a reference in engineering practice.

The optimized mix ratio of LC35 lightweight aggregate concrete is as follows: the dry mass ratio of each component is: fly ash: slag powder: cement: sand: ceramsite = 1:1:4.67:11.32:6.44. The water reducing agent is added according to 1.5% of the cement mass, and the water-binder ratio is 0.36.

The feature is that: the water-binder ratio is 0.36; the water reducer is 1.5% of the cement mass.

The cement used in the light concrete is P.O42.5 grade ordinary portland cement; the sand adopts natural graded river sand, which is in Zone 2, and the grade is good. The sand fineness modulus Mx=2.48 is medium sand The bulk density is 1604kg/m ³ ; the coarse aggregate used is 700-grade ceramsite with a dry density of 746kg/m ³ .

The advantage of the present invention is that it uses easily obtained materials such as fly ash, slag powder, cement, sand, ceramsite, etc., and the added fly ash and slag powder are industrial by-products, which reduces the cost of concrete. In the experiment design, 9 kinds of mix ratios were drawn up for experiments, and the optimized concrete mix ratios were obtained through comparative analysis. The lightweight aggregate concrete obtained through the optimization of the mix ratios has higher strength. The prepared LC35 lightweight aggregate concrete provides a reference for structurally replacing C30 ordinary concrete.

Detailed ways

Preparation method 1: According to the dry mass ratio of various main materials during preparation, the ratio of fly ash: slag powder: cement: sand: ceramsite = 1:1:4.67:11.32:6.44, the water reducer is 1.5% of the cement mass % filling, add water according to the water-to-binder ratio of 0.36. Accordingly, the amount of each material per unit volume is converted. Then, according to each mixing amount of the mixing machine, determine the feeding amount of various materials at one time. Note that the moisture content of sand and ceramsite should be measured before batching, and sand and ceramsite should be prepared according to dry weight. All kinds of dry materials should be mixed evenly, the admixture is added to the water, and then the water reducer is added to the water according to 1.5% of the cement mass and mixed well, then added to the dry materials, and all materials are mixed evenly by mechanical stirring, pouring Put it into the test mold, vibrate and compact it, and keep in good health.

Preparation method 2: According to the dry mass ratio of various main materials during preparation, the ratio of fly ash: slag powder: cement: sand: ceramsite = 1:1:4.67:11.32:6.44, the water reducer is 1.5% of the cement mass % filling, add water according to the water-to-binder ratio of 0.36. Accordingly, the amount of each material per unit volume is converted. Then, according to the mixing amount of the mixing machine, determine the feeding amount of various materials at one time. Note that the water content of sand and ceramsite should be measured before batching, and sand and ceramsite should be prepared according to dry weight. The mixing order of the concrete mixture is: water and admixture are mixed first, and then they are evenly mixed with cement, the formed cement slurry is then mixed with sand to form mortar, and finally the mortar is mixed with ceramsite. Note that the materials in each step should be mixed evenly, and it is advisable to adopt the method of mechanical stirring. After mixing and stirring evenly, enter the next step. After mixing all kinds of materials evenly, pour them into the test mold, vibrate and compact, and keep healthy.

Claims (4)

1., through a LC35 level light structures concrete for mixtures optimal design, employing main raw is flyash, slag powders, cement, haydite, water.It is characterized in that: described each dry component mass ratio is: flyash: slag powders: cement: sand: haydite=1:1:4.67:11.32:6.44.The light concrete apparent density 1922kg/m of preparation ³.The trinity mixture fill 28 days ultimate compression strength of preparation reaches more than 37MPa, meets the requirement of LC35 lightweight aggregate concrete.This proportioning can with reference to application in engineering reality.

2. LC35 level light weight concrete according to claim 1, is characterized in that: described water reducer is dosed by 1.5% of cement quality; The water-cement ratio of concrete mix is 0.36.

3. LC35 level light weight concrete according to claim 1, is characterized in that: the cement of employing is PO42.5 level ordinary Portland cement; Sand adopts the river sand of prototype gradation, is in 2nd district, and grating is good, and sand fineness modulus Mx=2.48 is medium sand, tap density 1604kg/m ³; The coarse aggregate adopted is dry density 746kg/m ³700 grades of haydites.

4. LC35 light weight concrete according to claim 1, it is characterized in that: the various materials needed for preparation will by certain feeding sequence successively by even for various material mixing, but first admixture will be added to the water, adopt churned mechanically mode, by even for all material mix, pour into template, vibration compacting, health.