As a new type of building material, ready-mixed mortar has many advantages, such as stable quality, convenient construction and good environmental performance. However, the popularization of ready-mixed mortar still faces problems in terms of cost, material quality and project quality. In this paper, we will discuss these key issues and put forward corresponding ideas to solve them.
Costs
Material Costs
The main raw materials of wet-mixed mortar include cement, sand, fly ash stone powder and additives, which are basically the same as those of concrete. Concrete companies have the advantage of large-scale centralized purchasing, and their material procurement costs are much lower than bulk purchasing at the site.
Manufacturing Costs
The original automated production line of the commercial concrete plant can be slightly modified to produce wet mortar. Compared with the dry mortar plant, the commercial concrete plant does not need to additionally consider the depreciation cost of the plant investment, and it can also superimpose the output of wet mortar with the output of concrete to jointly share the fixed costs of the production and operation. Therefore, the manufacturing cost is also lower than processing and mixing mortar at the construction site.
Distribution Costs
Wet mortar can be directly transported by concrete mixer trucks, avoiding the investment of re-purchasing dry mortar transportation trucks. The distribution cost of wet mortar can be comparable to that of concrete. In contrast, ready-mixed mortar needs to transport raw materials such as river sand and cement separately to the construction site, and the transportation cost of the distribution method is higher.
Quality of materials
Definition of open time
Open time (Hk) means that the performance indexes of mortar mix meet the following four requirements at the same time within the specified time Hk:
Loss of consistency <10% (refer to but not equal to GB25181-2010 ready-mixed mortar)
The rate of change of water secretion is ≤5% (refer to but not equivalent to GB/T50080 Standard Test Method for Performance of Ordinary Concrete Mix)
Setting time <1.3Hk (refer to GB25181-2010 ready-mixed mortar)
Volume change rate <5% (refer to but not equivalent to JGJ/T70 standard of basic performance test method for construction mortar)
Guiding significance of “open time” to the production and application of wet mortar
Open time is a new concept describing the constructability of mortar mix, which is a comprehensive index characterizing the whole process of construction of wet-mixed mortar from the production of mixing plant, transportation to the site for storage, secondary transportation and plastering operation. Unlike the setting time, the opening time can better reflect the quality requirements of the whole process of wet mortar in centralized production, centralized distribution and on-site pick-up and use. In this way, when the production task of wet-mixed mortar becomes bigger, according to the order plan of the next day of the construction site, the wet-mixed mortar can be centrally produced in the evening and centrally distributed to the construction site in advance on the same evening, maximizing the potential of the mixing plant’s production equipment and transportation vehicles.
Project Quality
Conversion of the main body responsible for the quality of plastering works
After the constructability of wet-mixed mortar meets the requirements, the key to the quality of mortar plastering project lies in avoiding problems such as hollowing, cracking and seepage of the plastering layer. In the past, the quality control of ready-mixed mortar was the responsibility of the plasterer’s class, so the repair costs caused by the hollowing and cracking of the plaster layer were mostly absorbed by the plasterer’s class. After the replacement of ready-mixed mortar by ready-mixed mortar, the responsible body for the quality of mortar materials has changed to the mortar factory, and the plasterer’s class is no longer willing to pay the bill for the repair works, resulting in a concentrated outbreak of complaints about the quality of mortar works.
Solutions to the problems of hollowing, cracking and leaking
There are many factors affecting mortar hollowing and cracking, and mortar quality is only one of them, and quality plastering project needs comprehensive treatment. Although the relevant construction specification for plastering works is already very complete, for this new product form of wet-mixed mortar, a simple and reliable supporting technical measures are needed to completely solve the hollowing and cracking of the plaster layer, and such new measures should not increase the comprehensive cost of the construction site. For this reason, a concrete interface treatment agent and the supporting construction process were developed, which had a significant effect and was recognized by most of the constructors.
Conclusion
With the popularization of ready-mixed mortar in the construction industry, its problems in terms of cost, material quality and project quality have gradually been solved. In the future, ready-mixed mortar will continue to develop and grow under the support of national policies and become an important part of green building.
Frequently Asked Questions
What is the difference between ready-mixed mortar and traditional mortar?
Ready-mixed mortar is a mortar in which various materials are pre-mixed in a factory according to a certain ratio, while traditional mortar is prepared temporarily at the construction site. Ready-mixed mortar is more stable in quality, more convenient in construction and better in environmental protection.
What are the advantages of using ready-mixed mortar?
Ready-mixed mortar has the advantages of stable quality, convenient construction, good environmental performance, cost control, etc. It is widely used in all kinds of construction projects.
How to choose suppliers of ready-mixed mortar?
When choosing suppliers of ready-mixed mortar, you should consider their qualification, production capacity, product quality, service level and other factors to ensure that the selected suppliers can provide quality and reliable products and services.
What is the environmental performance of ready-mixed mortar?
The production process of ready-mixed mortar involves less dust and noise pollution, which is in line with the environmental requirements of modern construction and helps to reduce pollution and energy consumption in the construction process.
What are the prospects for the application of ready-mixed mortar in future construction?
With the support of national policy and the growth of market demand, the application of ready-mixed mortar in future construction has a broad prospect and will become an important part of green building.