阅读说明：本技术 一种预拌砂浆及其应用 (Premixed mortar and application thereof ) 是由 王淼 李岩凌 刘文才 何强 周伟 陈向杰 于 2021-08-02 设计创作，主要内容包括：本发明涉及一种预拌砂浆,包含主料和辅料,其中,主料包含按重量分数计的以下材料：胶凝材料12～17％,摻合料12～17％,再生骨料68～71％；按预拌砂浆总重量分数计,辅料包含保水剂0.02％,减水剂0.025％,聚乙烯醇0.01％；胶凝材料为矿渣硅酸盐水泥和/或硅酸盐水泥,再生骨料为混凝土再生骨料和红砖再生骨料中的一种或两种,摻合料为二级粉煤灰,再生骨料颗粒粒径为0～10mm,再生骨料制备成预拌砂浆前经过高温煅烧降温冷却,所述高温煅烧温度为1330℃,煅烧时间为80min。本发明预拌砂浆不仅仅充分利用再生混凝土做骨料,更使用了红砖再生骨料,为大量的红砖建筑垃圾找到的再利用的途径。(The invention relates to ready-mixed mortar, which comprises main materials and auxiliary materials, wherein the main materials comprise the following materials in parts by weight: 12-17% of a cementing material, 12-17% of a doping material and 68-71% of a recycled aggregate; the auxiliary materials comprise 0.02 percent of water retention agent, 0.025 percent of water reducing agent and 0.01 percent of polyvinyl alcohol according to the total weight fraction of the ready-mixed mortar; the cementing material is slag portland cement and/or portland cement, the recycled aggregate is one or two of concrete recycled aggregate and red brick recycled aggregate, the doping material is secondary fly ash, the particle size of recycled aggregate particles is 0-10 mm, the recycled aggregate is calcined at high temperature and cooled down before being prepared into the ready-mixed mortar, the high-temperature calcination temperature is 1330 ℃, and the calcination time is 80 min. The premixed mortar not only fully utilizes recycled concrete as aggregate, but also utilizes red brick recycled aggregate, and provides a way for recycling a large amount of red brick construction waste.)

1. The ready-mixed mortar comprises main materials and auxiliary materials, wherein the main materials comprise the following materials in parts by weight: 12-17% of a cementing material, 12-17% of a doping material and 68-71% of a recycled aggregate; the auxiliary materials comprise 0.02 percent of water retention agent, 0.025 percent of water reducing agent and 0.01 percent of polyvinyl alcohol according to the total weight fraction of the ready-mixed mortar; the cementing material is slag portland cement and/or portland cement, the recycled aggregate is one or two of concrete recycled aggregate and red brick recycled aggregate, the doping material is secondary fly ash, the particle size of recycled aggregate particles is 0-10 mm, the recycled aggregate is subjected to high-temperature calcination, temperature reduction and cooling before being prepared into premixed mortar, the high-temperature calcination temperature is 1330 ℃, and the calcination time is 80 min.

2. The ready-mixed mortar according to claim 1, wherein the cementitious material is 14 wt%, the secondary fly ash is 13-17 wt%, and the recycled aggregate is 68-70 wt%.

3. The ready-mixed mortar of claim 1, wherein the portland cement is 14 wt%, the secondary fly ash is 16 wt%, the recycled aggregate is 70 wt%, the water retention agent is cellulose ether, the water reduction agent is a naphthalene water reduction agent, and the recycled aggregate particles have a particle size of 5-10 mm.

4. The ready-mixed mortar according to claim 2, wherein the recycled concrete aggregate is 20-30% by weight.

5. The ready-mixed mortar of claim 4, wherein the recycled concrete aggregate is 25% by weight.

6. Use of a ready-mixed mortar according to any one of claims 1 to 5 in plastering ready-mixed mortar.

Technical Field

The invention relates to the technical field of civil engineering materials, in particular to ready-mixed mortar and application thereof.

Background

The premixed mortar is used as a powdery mixed material, is generally a non-load-bearing material in a building, has low strength requirement, realizes the utilization of the construction waste recycled aggregate in the premixed mortar, can effectively save resources and protect the environment, and can realize the sustainable development of the society.

The main components of the construction waste are concrete, bricks and tiles, mortar, wood chips, plastics, foam and other impurities. The performances of concrete, red brick and mortar have great difference. The concrete has high strength mark, and contains large-particle-size aggregates such as stones and pebbles, and the like, after the concrete is subjected to construction processes such as pumping, vibrating and the like, the finished product is compact, and after the concrete is treated by a treatment line, the crushed recycled aggregates have good quality, high strength and low water absorption; the brick and tile have low strength, the interior of the brick and tile is a porous structure after sintering and molding, and the crushed recycled aggregate has low strength and high water absorption after treatment by a treatment line; the mortar material has low strength, fine aggregate and poor performance, and the crushed recycled aggregate has low strength and high water absorption after being treated by a treatment line.

Research on recycled aggregate in concrete and ready-mixed mortar is started in scientific research institutes more than ten years ago, but the main component of the recycled aggregate is recycled concrete aggregate, even recycled aggregate crushed after concrete is stripped of cement stone, the performance index of the recycled aggregate is reduced compared with that of natural aggregate, but the recycled aggregate is very close to the natural aggregate, the application technology of the recycled concrete aggregate in the ready-mixed mortar is relatively mature, but the recycled ready-mixed mortar is not well popularized and applied, and the biggest reason is that the recycled concrete aggregate is lack of resources and cannot meet the production requirements of ready-mixed mortar enterprises.

The buildings dismantled at the present stage are mainly used for reconstructing old houses in shed areas in cities or dismantling self-built houses in rural areas, the main structural forms of the two types of buildings are mainly red bricks, and the concrete content is little. The construction waste mainly comprising red bricks is the main component of the existing construction waste, but the application problem of the construction waste recycled aggregate mainly comprising red bricks is not well recognized, and how to realize the application problem of the red brick recycled aggregate is the key point of resource utilization of the construction waste.

Disclosure of Invention

Based on this, there is a need to provide a ready-mixed mortar.

The ready-mixed mortar comprises main materials and auxiliary materials, wherein the main materials comprise the following materials in parts by weight: 12-17% of a cementing material, 12-17% of a doping material and 68-71% of a recycled aggregate; the auxiliary materials comprise 0.02 percent of water retention agent, 0.025 percent of water reducing agent and 0.01 percent of polyvinyl alcohol according to the total weight fraction of the ready-mixed mortar; the cementing material is slag portland cement and/or portland cement, the recycled aggregate is one or two of concrete recycled aggregate and red brick recycled aggregate, the doping material is secondary fly ash, the particle size of recycled aggregate particles is 0-10 mm, the recycled aggregate is subjected to high-temperature calcination, temperature reduction and cooling before being prepared into premixed mortar, the high-temperature calcination temperature is 1330 ℃, and the calcination time is 80 min.

In one embodiment, the weight percentage of the cementing material is 14%, the weight percentage of the secondary fly ash is 13-17%, and the weight percentage of the recycled aggregate is 68-70%.

In one embodiment, the recycled aggregate is characterized in that the Portland cement is 14% by weight, the secondary fly ash is 16% by weight, the recycled aggregate is 70% by weight, the water-retaining agent is cellulose ether, the water-reducing agent is a naphthalene water-reducing agent, and the particle size of the recycled aggregate is 5-10 mm.

In one embodiment, the recycled concrete aggregate accounts for 20-30%.

In one embodiment, the recycled concrete aggregate is 25%.

The invention provides the application of the ready-mixed mortar in plastering and ready-mixed mortar.

The invention has the beneficial effects that:

the premixed mortar prepared by replacing natural aggregate with the recycled aggregate prepared from the building waste can ensure that the consistency loss of the premixed mortar is not obvious after 2 hours, the compressive strength of the mortar meets the use standard, and the premixed mortar is excellent recycled aggregate premixed mortar.

Drawings

FIG. 1 is the effect of different proportions of concrete aggregate on the strength of plastering mortar in example 1;

FIG. 2 is the effect of different proportions of concrete aggregate on the strength of plastering mortar in example 2;

FIG. 3 is the effect of different proportions of concrete aggregate on the strength of plastering mortar in example 3;

FIG. 4 is a graph showing the effect of different proportions of concrete aggregate on the consistency loss of plastering mortar for 2 hours in examples 1, 2 and 3;

FIG. 5 is a graph of the effect of cementitious material on the performance of a plastering mortar;

FIG. 6 is a graph showing the effect of cement on the 2h consistency loss rate.

Detailed Description

The invention is further described below with reference to specific embodiments. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Example 1

The ready-mixed mortar in the embodiment comprises main materials and auxiliary materials, wherein the main materials comprise the following materials in parts by weight: 14% of Portland cement, 16% of secondary fly ash, 70% of concrete recycled aggregate and red brick recycled aggregate, wherein the total amount of the concrete recycled aggregate and the red brick recycled aggregate is 70%, and the particle size of the recycled aggregate is 5-10 mm. According to the total weight fraction of the ready-mixed mortar, the auxiliary materials comprise: 0.02% of water-retaining agent, 0.025% of water reducing agent and 0.01% of polyvinyl alcohol, and the recycled aggregate is calcined at high temperature, cooled and cooled before being prepared into ready-mixed mortar, wherein the high-temperature calcination temperature is 1330 ℃, and the calcination time is 80 min.

Example 2

The ready-mixed mortar in the embodiment comprises main materials and auxiliary materials, wherein the main materials comprise the following materials in parts by weight: 15% of Portland cement, 17% of secondary fly ash, 68% of concrete recycled aggregate and red brick recycled aggregate, and the particle size of the recycled aggregate is 5-10 mm. According to the total weight fraction of the ready-mixed mortar, the auxiliary materials comprise: 0.02% of water-retaining agent, 0.025% of water reducing agent and 0.01% of polyvinyl alcohol, and the recycled aggregate is calcined at high temperature, cooled and cooled before being prepared into ready-mixed mortar, wherein the high-temperature calcination temperature is 1330 ℃, and the calcination time is 80 min.

Example 3

The ready-mixed mortar in the embodiment comprises main materials and auxiliary materials, wherein the main materials comprise the following materials in parts by weight: 17% of Portland cement, 12% of secondary fly ash, 71% of concrete recycled aggregate and red brick recycled aggregate, and the particle size of the recycled aggregate is 5-10 mm. According to the total weight fraction of the ready-mixed mortar, the auxiliary materials comprise: 0.02% of water-retaining agent, 0.025% of water reducing agent and 0.01% of polyvinyl alcohol, and the recycled aggregate is calcined at high temperature, cooled and cooled before being prepared into ready-mixed mortar, wherein the high-temperature calcination temperature is 1330 ℃, and the calcination time is 80 min.

Comparative example 1

This comparative example differs from example 1 in that the aggregate used was a natural aggregate.

Test example

The ready-mixed mortars of examples 1 to 3 and comparative example were tested for performance, with test parameters including water demand, initial consistency, 2h consistency loss, wet volume weight, 7d compressive strength, 28d compressive strength, strength loss, mass loss mean. In examples 1 to 3, the concrete recycled aggregate doping amounts were adjusted from 0% to 100%, and the results are shown in tables 1 to 3. Comparative example 1 was tested to give table 4.

TABLE 1

As can be seen from Table 1, with the decrease of the concrete aggregate proportion in the recycled aggregate and the increase of the red brick aggregate proportion, the water demand of the plastering mortar is increased, and the water demand of the pure red brick aggregate is increased by 4.2 percent compared with that of the pure concrete aggregate; meanwhile, the wet volume weight is in a descending trend. The main reason is that the red brick recycled aggregate has high internal porosity, so that the red brick fine aggregate has light volume weight and high water absorption.

The results of frost resistance tests on plastering mortar with different proportions of concrete aggregate show that the concrete recycled aggregate and the red brick recycled aggregate have compressive strength loss of less than 25 percent and mass loss of less than 5 percent under different proportion conditions, and the results show that the compressive strength loss and the mass loss have no obvious reduction trend along with the increase of the proportions of the concrete aggregate.

As can be seen from figure 1, under the condition of the basic mixing proportion of 14 percent of cement and 16 percent of fly ash, the mixing amount of the concrete in the recycled aggregate is from 0 to 100 percent, and the compressive strength of the plastering mortar meets the requirement of M10 strength. The proportion of concrete aggregate has certain influence on the pressure resistance, but the influence degree is not large; the water requirement of the brick and tile recycled aggregate plastering mortar is 30.5 percent, the water requirement of the concrete recycled aggregate plastering mortar is 26.3 percent, and the 28d strength red brick recycled aggregate of the plastering mortar is greater than the concrete recycled aggregate, so the analysis reason is mainly that the water absorption capacity of the red brick recycled aggregate is large, after the plastering mortar is condensed, the water in the red brick recycled aggregate is slowly released, the hydration of cement in the plastering mortar is promoted, and the plastering mortar has high compressive strength. On the other hand, the analysis shows that the crushing value of the red brick recycled aggregate is not high, but the compressive strength of the red brick recycled aggregate product can completely reach that of the concrete recycled aggregate product for a product with low strength.

As can be seen from Table 2, with the decrease of the concrete aggregate proportion in the recycled aggregate and the increase of the red brick aggregate proportion, the water demand of the plastering mortar is increased, and the water demand of the pure red brick aggregate is increased by 4.6 percent compared with that of the pure concrete aggregate; meanwhile, the wet volume weight is in a descending trend. The main reason is that the red brick recycled aggregate has high internal porosity, so that the red brick fine aggregate has light volume weight and high water absorption.

The results of frost resistance tests on plastering mortar with different proportions of concrete aggregate show that the concrete recycled aggregate and the red brick recycled aggregate have compressive strength loss of less than 25 percent and mass loss of less than 5 percent under different proportion conditions, and the results show that the compressive strength loss and the mass loss have no obvious reduction trend along with the increase of the proportions of the concrete aggregate.

As can be seen from figure 2, under the condition of the basic mixing proportion of 15 percent of cement and 17 percent of fly ash, the mixing amount of the concrete in the recycled aggregate is from 0 to 100 percent, and the compressive strength of the plastering mortar meets the requirement of M10 strength. The proportion of concrete aggregate has certain influence on the pressure resistance, but the influence degree is not large; the water requirement of the plastering mortar of the brick and tile recycled aggregate is 30.8 percent, the water requirement of the plastering mortar of the concrete recycled aggregate is 26.2 percent, and the 28 d-strength red brick recycled aggregate of the plastering mortar is larger than the concrete recycled aggregate, so the analysis reason is mainly that the water absorption capacity of the red brick recycled aggregate is large, after the plastering mortar is condensed, the water in the red brick recycled aggregate is slowly released, the hydration of cement in the plastering mortar is promoted, and the plastering mortar has high compressive strength. On the other hand, the analysis shows that the crushing value of the red brick recycled aggregate is not high, but the compressive strength of the red brick recycled aggregate product can completely reach that of the concrete recycled aggregate product for a product with low strength.

TABLE 2

As can be seen from Table 3, with the decrease of the concrete aggregate proportion in the recycled aggregate and the increase of the red brick aggregate proportion, the water demand of the plastering mortar is increased, and the water demand of the pure red brick aggregate is increased by 4.5 percent compared with that of the pure concrete aggregate; meanwhile, the wet volume weight is in a descending trend. The main reason is that the red brick recycled aggregate has high internal porosity, so that the red brick fine aggregate has light volume weight and high water absorption.

The results of frost resistance tests on plastering mortar with different proportions of concrete aggregate show that the concrete recycled aggregate and the red brick recycled aggregate have compressive strength loss of less than 25 percent and mass loss of less than 5 percent under different proportion conditions, and the results show that the compressive strength loss and the mass loss have no obvious reduction trend along with the increase of the proportions of the concrete aggregate.

TABLE 3

As can be seen from figure 3, under the condition of the basic mixing proportion of 17 percent of cement and 12 percent of fly ash, the mixing amount of the concrete in the recycled aggregate is from 0 to 100 percent, and the compressive strength of the plastering mortar meets the requirement of M10 strength. The proportion of concrete aggregate has certain influence on the pressure resistance, but the influence degree is not large; the water requirement of the brick and tile recycled aggregate plastering mortar is 30.6 percent, the water requirement of the concrete recycled aggregate plastering mortar is 26.1 percent, and the 28d strength red brick recycled aggregate of the plastering mortar is greater than the concrete recycled aggregate, so the analysis reason is mainly that the water absorption capacity of the red brick recycled aggregate is large, after the plastering mortar is condensed, the water in the red brick recycled aggregate is slowly released, the hydration of cement in the plastering mortar is promoted, and the plastering mortar has high compressive strength. On the other hand, the analysis shows that the crushing value of the red brick recycled aggregate is not high, but the compressive strength of the red brick recycled aggregate product can completely reach that of the concrete recycled aggregate product for a product with low strength.

As can be seen from FIG. 4, when the concrete aggregate accounts for more than 64%, the thickness loss of the plastering mortar is less than 24%, but the fluctuation is large, and no obvious change rule exists; when the concrete aggregate proportion is less than 64%, the thickness loss of the plastering mortar after 2 hours tends to increase along with the reduction of the concrete recycled aggregate proportion, the concrete aggregate is 0, and the thickness loss of the plastering mortar after 2 hours is close to 30%.

In conclusion, when the recycled aggregate is applied to the plastering mortar, the compression strength and the frost resistance of the plastering mortar are not greatly influenced, the water retention rate and the bonding strength of the plastering mortar are more influenced by the additive, the recycled aggregate is applied to the plastering mortar instead of the natural aggregate, the index of the 2h consistency loss rate is the biggest influence on the performance of the plastering mortar, and the problem how to solve the 2h consistency loss rate is also the main problem of realizing the application of the recycled aggregate to the ready-mixed mortar because the water absorption rate of the recycled aggregate is greater than that of the natural aggregate.

TABLE 4

As can be seen from tables 1, 2, 3 and 4, the performance of the ready-mixed mortar prepared by using the recycled aggregate is equivalent to that of the ready-mixed mortar prepared by using the natural aggregate, but the recycled concrete aggregate and the red brick recycled aggregate are used in the invention, so that a large amount of construction waste is utilized, and the resource utilization of the construction waste is realized.

In the plastering mortar taking 42.5 common portland cement as a cementing material in the figure 5, the 28d compressive strength reaches the requirement of 10MPa under the condition that the addition amount reaches 12 percent. In FIG. 6, the addition amount of the gelling material is 14%, the addition amount is in the range of 12% -17%, the consistency loss rate is reduced within 2h, and gradually reduced from 29% to 20%, but the compressive strength is reduced due to the increase of water demand.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.