TANZANIA - #likelafargeholcim

For building tips and information, follow us on

How to fix common concrete slab problems

How to fix common concrete slab problems

When working with concrete, contractors may encounter a few different problems. The following issues can sometimes occur when pouring concrete slabs. While some aspects of working with concrete slabs have changed over the years, many issues have not. Here are three common problems that come with pouring concrete slabs, and their possible solutions.

1) Excessive Bleeding

Bleeding occurs when the heavy ingredients in concrete (aggregate and sand) settle and push the extra water to the top of the slab. Concrete that bleeds for too long or too fast can cause problems like sand streaks in walls; weak horizontal construction joints; rock jams in pump lines; etc. Finishing a concrete slab before bleed water has evaporated can cause cracking, dusting, scaling and low-wear resistance.

Excessive bleeding can be avoided by not adding too much water to the concrete; placing concrete at the lowest possible slump (if you need a higher slump to speed placement, consider using a superplasticizer); using a more finely ground cement; adding more cement to the mix; blending in a fine blow sand or fly ash.

2) Curling

Curling happens when a slab rises up at corners and edges – or sometimes at a mid-panel crack. It happens when the top section of a concrete slab dries or cools faster than the bottom section. Curled concrete slabs can be fixed, but it is expensive. 

Grinding can level out the edges, and grout can be used to restore support to the slab. The best way to avoid curling is to control it before it happens. There are a number of material choices, construction practices and design decisions that will help prevent curling from happening in the first place.

3) Thin slab

All concrete slabs have varied thicknesses – some parts of the slab are thicker than others. When it comes to thin slabs, the thinnest sections may be too thin to retain their strength and may be prone to crumbling. In such cases, the contractor needs to decide how thin is too thin.

They must decide whether to make the slabs thicker for the sake of giving additional strength and durability to the concrete slab. Contractors should also pour thin slabs very carefully and ensure that the depth of concrete is even throughout the slab.

These are three of the most common problems that can arise when working with concrete slabs. They are easy to fix; taking care while pouring the concrete and being precise with measurements is the best way to avoid these problems in the first place.


LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges. 


LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.


At LafargeHolcim Tanzania, we believe customers come first. We listen to your specific requirements to supply and develop the best solutions for your needs. As the new leader in building materials, you can also rely on our cutting-edge research and development capabilities that have resulted in the finest materials for your construction projects, whether large or small.


Follow us on Facebook, Twitter, LinkedIn and Pinterest for the best tips on construction, handy projects and the latest industry news. See our Instagram channel for more insights into our products.

Synthetic fibres can increase the durability of concrete

Contractors sometimes add synthetic fibres to their concrete mix. These fibres of man-made polymers are specifically engineered to withstand the long-term alkaline environment within a concrete mix. They are used to minimise cracking, lower the permeability of the concrete and increase the strength of the structure. They act as a secondary reinforcement element; the primary …

The eight types of construction company

There are many different types of construction company. Not all contractors specialise in the same fields and not all companies do the same construction work. Depending on the type of work they do, construction companies can be classified into the following eight types: 1. General contractors A general contractor provides all of the labour, equipment, …

How to prevent dampness in a building

Dampness in a building may occur due to faulty construction, the use of poor-quality building materials or bad architectural design. Dampness affects the lifespan of a building or structure, but it also creates unhygienic conditions. Mold and fungi love to grow in damp conditions, so it is best to fix any signs of wet concrete …

The importance of having a schedule for a construction project

Construction projects are delicate operations that need to run on time in order to stay within the allocated budget. As soon as a project is delayed, it costs the contractors and building owners more money. Having a strict schedule is important as it keeps the project on time and allows all workers to know when …

How to prepare a concrete surface for a topping

Sometimes concrete surfaces are given a decorative topping that adds further protection and durability to a floor or carpark. The underlying concrete will need to be prepared properly before any topping is laid on top. This will ensure that a good bond is formed between the two materials and that no cracks or chips will …