Site Problems During Masonry Construction
Masonry construction is a popular choice for building structures due to its durability and aesthetic appeal. However, like any construction process, there are common site problems that can arise during masonry construction.
In this article, we will discuss some of these issues and explore ways to prevent or mitigate them, ensuring the successful completion of masonry projects.
1. Incorrect Mix Proportions:
One of the most common site problems encountered during masonry construction is the use of incorrect mix proportions. This issue typically arises when the binder materials, such as cement and lime, are not measured accurately. While construction codes and documents specify measuring the binder material by weight or volume, this crucial step is often overlooked when materials are mixed on-site. In some cases, an imprecise measuring technique, such as counting shovels, is used, leading to inconsistent mix proportions. To address this problem, it is essential to accurately measure all mix constituents, ensuring the proper ratio of binder materials for optimal mortar quality.
2. Use of Unauthorized Admixtures:
Another prevalent issue is the unauthorized use of admixtures in mortar. This problem occurs when air entraining admixtures, such as domestic detergents or washing up liquids, are added without proper authorization. While these admixtures may improve mortar plasticity and ease of use, excessive air entrainment can compromise the strength and bond of the mortar. To prevent this problem, it is crucial to adhere to approved admixtures and follow the recommended dosage guidelines, ensuring the integrity of the mortar.
3. Sulphate Attack:
Sulphate attack is a significant concern during masonry construction, resulting from the reaction between soluble sulphate and tricalcium compounds present in Portland cement. This reaction produces expansive ettringite, which exerts pressure on the masonry, leading to spalling, degradation, and potential failure. To prevent sulphate attack, suitable measures must be taken, such as preventing sulphate from reaching the mortar. This can be achieved through proper detailing of damp-proof courses and related construction elements. Additionally, designing coping and overhangs to avoid saturation can reduce the risk of sulphate attack. The use of air entraining agents in the mortar can also help mitigate this problem.
4. Freeze and Thaw Cycles:
Masonry elements exposed to cycles of freezing and thawing can suffer degradation and eventual failure. Water saturation within the masonry, followed by freezing, causes expansion and can lead to cracking, spalling, and loss of structural integrity. To protect masonry members from the effects of freezing and thawing, suitable damp-proof courses and copings should be introduced. Furthermore, the use of air entraining agents in the mortar has proven to be beneficial in safeguarding masonry constructions from freeze and thaw cycles, as well as sulphate attacks.
5. Aesthetic Failures:
While aesthetics do not directly impact the load-carrying capacity of masonry members, they play a crucial role in the overall visual appeal of a structure. Aesthetic failures, such as the formation of efflorescence or disfiguring stains, are not desirable to clients. To prevent these issues, it is important to take necessary actions during construction, such as covering newly constructed masonry at the end of each day to prevent saturation. This will help maintain the aesthetic appearance of the masonry. Additionally, protecting hydrated Portland cement from leaching and surface staining is essential to ensure a visually pleasing outcome.
Awareness of common site problems during masonry construction is vital for ensuring the successful completion of projects. By addressing issues such as incorrect mix proportions, unauthorized admixtures, sulphate attack, freeze and thaw cycles, and aesthetic failures, construction professionals can enhance the quality and durability of masonry structures.
Following recommended practices, adhering to construction codes, and employing preventive measures will contribute to the long-term success and satisfaction of masonry projects, both in terms of functionality and visual appeal.