In response to widespread misconceptions in the construction industry regarding the differences between mortars, plasters and concrete, Quantum Ready
In response to widespread misconceptions in the construction industry regarding the differences between mortars, plasters and concrete, Quantum Ready Mixed Concrete has developed an informative poster to address these misunderstandings.
This initiative aims to educate contractors, plasterers and site managers on the correct application, handling and expectations of readymix mortars and plasters, ensuring improved efficiency and structural integrity in construction projects.
It addresses common misconceptions that mortar and concrete are synonymous materials which they are not. Major differences occur in a number of areas namely; Mortar is specifically designed to achieve a compressive strength of approximately 5 MPa at 28 days, whereas concrete is rarely specified at such a low strength. This is only one of some fundamental distinctions that significantly impact testing, application and performance.
Laboratories conducting mortar strength tests require specialised accreditation distinct from concrete testing as mortar exhibits unique performance characteristics. Unlike concrete, which follows a predictable strength gain from 7 to 28 days, mortar, particularly retarded mortar, can display substantial variations in early strength. Factors such as the timing of sample collection, the effect of retempering at the end of the retarded life cycle can further complicate accurate strength assessment. In some cases, cube stripping within 24 hours is impractical and may necessitate specialised handling protocols.
It is also worth noting that shortfalls in mortar supply often lead to construction disputes and cost overruns. Industry bodies recommend a wastage factor ranging from 20% to 200%, depending on the experience of site supervisors and management efficiency. Failure to account for variables such as perforated bricks or bricks with frogs in the bill of quantities can more than double the required mortar volume of mortar required.
Furthermore, deteriorating building sand quality has necessitated the use of higher-grade cement, making testing essential to ensure adequate bond strength and durability. Poor material selection, inadequate precautions, and improper post-application handling significantly increases long-term maintenance costs. Attempting to cut costs by neglecting thorough material analysis and corrective measures is a false economy that will inevitably lead to increased repair expenses or even structural failure.
Another common issue the poster helps to address is inconsistencies in on-site mortar mixing, particularly when different wheelbarrow sizes are used. Standard builder’s wheelbarrows have a 65-litre capacity, but with the influx of imported models of varying volumes, the incorrect cement-to-sand ratio often results in substandard mortar. Site labourers typically add a standard 50 kg bag of cement per wheelbarrow, unaware that a larger wheelbarrow requires proportionally more cement to maintain the correct mix ratio. This oversight leads to weaker, less durable mortar, compromising structural integrity.
The Advantages of Quantum Readymix Mortar Supply
Quantum Ready Mixed Concrete highlights the benefits of using freshly mixed mortar delivered via concrete trucks. A batch of as little as 3 m³ of readymix mortar, supplied first thing in the morning, offers several advantages over on-site mixing:
• Optimised Mix Design: The mortar is blended with carefully selected sands to meet industry specifications, reducing the risk of plaster cracking when handled and cured correctly.
• Increased Productivity: Immediate mortar availability eliminates delays caused by on-site mixing, adding up to two extra hours of productivity per day, or the equivalent of an additional workday per week.
• Reduced Labour Fatigue: Workers no longer need to manually mix mortar, allowing them to focus solely on transportation of the mortar, resulting in higher efficiency and better-quality workmanship.
• Minimised Waste and Pilferage: With no cement on site, material theft is totally eliminated, and the disposal of unsightly empty cement bags is eliminated.
• Enhanced Delivery Efficiency: The use of the truck-mounted conveyor can deliver mortar directly to the worksite, up to two storeys high, further streamlining the construction process and saving valuable time.
• Consistent Quality: The homogenously mixed mortar remains usable for up to eight hours, ensuring uniform performance throughout the workday as opposed to smaller batches haphazardly mixed and of dubious quality.
Quantum Ready Mixed Concrete has compiled these insights and best practices into a comprehensive poster, available free of charge to building and plastering contractors who wish to enhance their understanding of readymix mortars. This technical resource provides essential guidance on correct application methods, mix design considerations and site management strategies to maximise efficiency and structural performance. Concrete Connect has also included a version of the poster on page 20-21 of this issue.
To request a copy of the poster contact Charlene at Quantum Midrand on Tel: 010 446 6745.
