The permeability of mortar refers to the permeability performance of mortar due to the characteristics of pore structure in the natural state without external force. This performance has a very important impact on the use effect and service life of the mortar. This article will deeply discuss the related concepts, test methods, influencing factors, and methods of improving the permeability of mortar.

Related concepts of mortar permeability

The permeability of mortar refers to the permeability performance of mortar due to the characteristics of pore structure in the natural state. Mortar permeability mainly includes two aspects, namely water absorption and water permeability.

Water absorption

Water absorption refers to the ability of the mortar surface to absorb external moisture after being in contact with the surrounding environment. Mortar has strong water absorption, which will cause water to penetrate the mortar, causing problems such as deformation and cracks, and affecting the use effect and service life.

Water permeability

Water permeability refers to whether the pore structure inside the mortar can pass through the channel formed by the penetration of water so that the water can flow out from the inside of the mortar. The mortar has strong water permeability, which can avoid the accumulation of moisture inside the mortar, reduce the cracking and peeling of the mortar, and also improve the durability and service life of the mortar.

Test method of mortar permeability

To accurately evaluate the permeability performance of mortar, some relevant tests need to be carried out. Several commonly used test methods are introduced below.

Water absorption test

The water absorption test is one of the methods to evaluate the water absorption performance of mortar. During the test, the dry mortar test block needs to be soaked in water for a certain period, then taken out and wiped dry on the surface of the test block, and then weighed. By calculating the percentage increase in the weight of the test block, the water absorption of the mortar can be obtained.

Penetration testing

Permeability testing is one of the methods to evaluate the water permeability of mortar. During the test, it is necessary to exert a certain pressure on the mortar test block, flow water into the mortar through a certain flow rate, and then record the time and depth of water penetration. By calculating the penetration rate and penetration depth, the permeability coefficient of the mortar can be obtained to evaluate the permeability of the mortar.

Influencing factors of mortar permeability

The quality of mortar permeability is affected by many factors, and several important factors are introduced below.

Mortar composition

The difference in mortar composition will have a significant impact on its permeability. For example, in cement mortar, factors such as the type and amount of cement, the particle size, and the mix ratio of sand will all affect the permeability of the mortar.

Mortar Pore Structure

Mortar pore structure has a direct impact on its permeability. The finer and more complex the pore structure, the poorer the permeability of the mortar.

Construction environment

The construction environment is also one of the factors affecting the permeability of mortar. For example, a high temperature and dry environment will cause the surface of the mortar to dry quickly and form micro-cracks, which will affect the permeability of the mortar.

Mortar curing time

The curing time of mortar also has a certain influence on its permeability. During the curing process, the pore structure inside the mortar will gradually decrease, thereby affecting its permeability. Therefore, the curing time of the mortar should be well controlled during construction to avoid premature loading or cement curing.

How to improve the permeability of mortar

To improve the permeability of mortar, it is necessary to start from many aspects. Here are a few commonly used methods.

Choose the right mortar composition

According to different use environments and requirements, choose the appropriate mortar composition, for example, you can increase the number of water-permeable materials used, such as coarse sand, etc.

Control the mortar mix ratio

The adjustment of the mortar mix ratio is also one of the important means to improve the permeability of mortar. Reasonable adjustment of the proportion and amount of cement and sand can achieve better permeability.

Enhanced mortar surface protection

During the construction process, strengthening the protection of the mortar surface is also one of the important measures to improve the permeability of the mortar. For example, it can be covered with plastic film and other materials to avoid the rapid drying of the surface and the formation of micro cracks.

Control the curing time of mortar

The curing time of mortar also has an important impact on its permeability, so it is necessary to control the curing time of mortar during construction to avoid premature loading or cement curing.

Add water permeability additive

Water permeability additives can improve the permeability of mortar by changing the pore structure and increasing the porosity of mortar. For example, auxiliary agents such as water reducers, thickeners, and dispersants can be added.

Optimize the construction environment

To improve the permeability of mortar, it is also necessary to optimize the construction environment. In a high-temperature and dry environment, measures such as awnings can be used to keep the surface of the mortar moist and avoid the formation of micro-cracks. In addition, the base layer needs to be inspected and treated before construction to ensure the flatness and firmness of the base layer and avoid affecting the permeability of the mortar due to the uneven base layer.

Mortar permeability is one of the important indicators to measure the water permeability of mortar. It is affected by many factors, including mortar composition, mortar pore structure, construction environment, and mortar curing time. To improve the permeability of mortar, we can start by selecting the appropriate mortar composition, controlling the mortar mix ratio, strengthening the mortar surface protection, controlling the curing time of the mortar, adding water-permeable additives, and optimizing the construction environment. By taking these measures, the permeability of mortar can be effectively improved to meet different needs and requirements.

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