Why Concrete Blocks are Prone to Water Leak?

Concrete blocks are usually highly porous. Meaning water or other thin liquid can easily pass through concrete blocks. One can quickly notice the spongy appearance of concrete blocks. The small voids on the surface make an easy avenue for any type of moisture to penetrate using capillary pressure and migrate into the concrete blocks. It is crucial to understand the reasons behind the water leakage issue. If the engineers and project managers understand the issue from the core, water leakage in concrete blocks can be stopped completely.

A typical concrete mixture contains powdered Portland cement, sand, gravel, and water. The light concrete blocks are produced using clay, shale, or slate instead of gravel and sand. Hollow concrete blocks, the most common and popular concrete block, contain a void in the block’s interior, which drastically reduces the overall weight of the block. The lighter-weight concrete blocks bring many advantages, such as helping with the installation process. However, they are more prone to water leakage than other concrete blocks.

Degree of Porosity

The degree of porosity of a concrete block depends on several aspects.

• Due to specific requirements of the manufacturer
• Manufacturers may fabricate the available materials and downgrade the quality
• The ratio of Portland cement to water (More water, more permeability)
• Compaction ratio at the plant of the concrete manufacturer

A concrete block typically cures within sixteen to twenty-four hours in the manufacturing process in a high humid atmosphere and at an approximate temperature of one hundred degrees Fahrenheit. Shortly after completing the manufacturing process, concrete blocks are usually delivered to the project site and assembled to create the walls while the curing is still an ongoing process. The average curing period for most concrete blocks is between three weeks to four weeks. During this period, the concrete blocks become vulnerable to developing hairline cracks or creeping cracks. Such cracks are one of the primary ways for water to leak through the blocks.

Leaks at the Flashing

Apart from the concrete block’s composition, there are flashing issues that can cause water leakage in the concrete blocks. Usually, metal or a composite of membrane and runner are used for creating a drainage system and an impermeable water barrier throughout the masonry walls. This flashing system goes through the concrete block. If poor quality material is used in the system, it affects the concrete blocks and eventually downgrades the quality of the concrete blocks. The chemical reaction between the concrete and the metal from the flashing system may create holes in the concrete, which will allow water to seep through.

Honeycomb

Honeycomb is a faulty formation in the structure of concrete blocks. When the curing process is not rightly done, and the process gets corrupted by outside forces, a faulty and porous honeycomb structure is formed. The presence of a honeycomb dramatically enhances the probability of water leakage. Hence, upon discovering, the honeycomb issue should be treated immediately.

Corrupt Coarse Aggregate

If the materials in the mix are corrupted, the quality of the concrete blocks will be below, and they will be prone to water leakage. Coarse aggregate is one of the significant factors in leakage in concrete blocks. If the aggregates are poorly graded, dirt-contained, and more significant in size, the aggregates are considered corrupt. These corrupt aggregates increase the voids in concrete blocks and thereby increase the permeability, which results in water leakage.

Impure Fine Aggregate

If the fine aggregate is impure, the quality of concrete blocks will be at risk. Improper fineness in the fine aggregate will produce more voids in the concrete blocks and leave more holes open for water to leak through. In addition, if pollutants are present in the fine aggregate, more voids will be created during the curing process of concrete blocks. Both coarse and fine aggregates should be adequately moisturized and cleaned before mixing. The aggregates should be in saturated surface dry condition before getting mixed in the plant.

Reinforcement Bars

Old and rusty steel bars, shutter oil, and cement mortar may cause water leakage within the concrete blocks. In addition, over reinforcing may weaken the concrete blocks and leave them for water leakage. At the same time, a low amount of rust can improve the quality of the bond between the concrete and the steel bars. However, over reinforcement or high rust will create steel congestion, and the concrete placement will become extremely tough. Lastly, the concrete may fall at risk of forming honeycombing.

Admixtures

Admixtures are also crucial in water leakage through concrete blocks. If the admixtures are expired or used more than necessary, the concrete blocks will lose their inherent qualities. Moreover, if admixtures are mixed with inappropriate materials, the concrete blocks will react adversely and create open spaces within the blocks and allow water to leak through. Hence, admixtures should be applied according to the overall concrete mix design specifications. The location of the applications should also be kept in mind. To ensure high-quality concrete blocks, experimenting with the dosage and changing the type of admixtures during the process must be avoided.

Cement Type and Mixing Water

The type and quality of cement are significant factors in preparing high-grade concrete blocks. If the wrong type of cement is used or the quality of cement is poor, the outcome of concrete blocks will be poor too. It will produce weak concrete blocks with numerous voids. In addition, during the mixing process, proper freshness is required. If polluted water is used or salt water is used, the materials will not be adequately mixed. Instead, the materials will start a chemical reaction with the water and form poor concrete blocks. Nowadays, the usage of superplasticizers is increasing instead of freshwater. Superplasticizers can achieve the required workability while significantly decreasing the chance of water leakage in concrete blocks. However, the application of superplasticizer should be made under the supervision of an experienced engineer.

Deviation from Designed Mix Ratio

The proper ratio of materials is very crucial in the process of making concrete blocks. If the ratio gets deviated, the quality will deviate as well. Often, manufacturers tweak the ratio to adjust to the customer demands. However, during the tweaking, the correct ratio gets altered. Usually, manufacturers use a higher quantity of water and incorrect aggregates and create voids in the concrete blocks. These voids contribute to the future water leakage issue.

Concrete Placement Issue

Segregation and bleeding of concrete are significant issues when it comes to concrete placement. If anything goes wrong during that process, the concrete blocks will risk water leakage. The probability of segregation and bleeding is at its highest during concrete pumping. Therefore, a mix of concrete blocks should be created, considering that the concrete mixture will require pumping.

Workmanship Quality

The workmanship determines the quality of the concrete. If the workers are poor in mixing and preparing a poor framework for installation, the concrete blocks will be vulnerable to water leakage. In addition, the lack of clear cover, improper compaction of concrete, faulty curing process, and plumbing failure will add to the risk of water leakage in concrete blocks.

Hence, uniform mixing of concrete needs to be ensured. If the workers use a machine to mix the concrete materials, the virtual inspections should be very thorough and ensure a uniform mixture. The concrete mixture should be poured before it loses its workability. One can always use a retarder to increase the time frame in which concrete mixture can be placed, compacted, and completed.

The formwork of the concrete blocks should be appropriately sealed to prevent any escape of water from the fresh concrete mixture. Otherwise, the mixture will be at risk of forming a honeycomb formation. Manufacturers must not use polythene to seal the formworks as it can cause a separator effect on the concrete mixture.

Improper concrete Cover

The concrete mixture should be adequately covered. If there are any open spaces, the air will seep through and begin a chemical reaction with the mixture. It may corrupt the quality of the aggregates. This is crucial because if the aggregates get corrupted, the quality of the concrete block will be poor. There may be an increased number of holes for water to leak. Hence, the workers should use proper material to cover the concrete firmly.

Inadequate Curing

Curing is the most sensitive period in the process of preparing concrete blocks. If the ideal condition is not ensured during the curing process, cracks will form in the concrete blocks. Hence, ensuring the concrete gets an adequate atmosphere to continue the curing process is crucial. There are many curing methods that will induce an effective outcome. Steam curing can be a valuable method to ensure high water resistance in concrete blocks. The concrete should be kept in a moist condition for a smooth curing process.

Source: waterdamageplus

Summary

Water leakage in concrete blocks is a serious issue. It is the primary cause of most building defects. However, if water leakage issues get addressed immediately, the defects can be eradicated eight out of ten times. In modern times, the concrete industry is saturated with different concrete blocks. Some types of concrete blocks are not porous and highly resistant to water. However, if prepared to maintain all the precautions, traditional concrete blocks will be free from water leakage.

FAQ (Frequently Asked Questions)

Does water leakage in concrete blocks affect the steel?

Ans: Yes, it does. If there are any leaks in the concrete slabs, it will cause steel corrosion and simultaneously deteriorate the concrete blocks.

Can I use muddy water in the concrete mixture?

Ans: No. If the water contains mud, it will hamper the curing process, and a honeycomb structure may be formed.

Can I use an additive to my concrete blocks to stop water leakage?

Ans: Additive is the final answer to battle water leakage. If the water leakage issue is found early, it can be fixed by changing the concrete blocks.

Shall I use water-resistant concrete blocks in my garage?

Ans: No. You should instead use concrete blocks that are highly porous for your garage. Otherwise, during rain, there may be a water logging situation.

What additive can I use to prepare waterproof concrete blocks?

Ans: You can use a liquid-applied membrane on the surface of the concrete blocks to create water-resistant concrete blocks.