q Key Facts About Cement Prices, Concrete And Mortar Strengths Production in Ghana - Home Improvement

Key Facts About Cement Prices,  Concrete And Mortar Strengths Production in Ghana

This research will highlight some key facts on the types of cement mixes from different manufacturers or producers in Ghana, concrete and mortar strengths to be achieved per different types of cement used. The research will use key facts on cement production and manufacturing methods from Portland Cement Research Europe.

Dansoaa, a contemporary building materials and hardware store has researched into cement strengths and cement products mixes. This will provide information only to our customers with a view to selecting the type of cement required to achieving the needed concrete and mortar strengths, to reduce costs and also acquire knowledge and understanding of some aspects of construction and building materials. The knowledge will alleviate or assuage the confusion on good and bad cement type’s selection by most tradesmen and house builders in Ghana.

Looking for ideas and Prices on the selection of Cement types For Construction Contact Dansoaa Builder’s Merchant Store

Cement is used widely for construction, whether you are using cement for major house building project in Ghana in cities such as Accra, Tema, Cape Coast, Takoradi, Ashaiman, Afienya, Kumasi and parts of Ghana, for construction including bridges, concrete walls, pillars, embankments, underground tunnels for roads and rail or to minor DIY projects such as renovation and paving works, the result you will achieve depends on a combination of factors.

Some of these factors are :

(1) the types or grades of cement used,

(2) A mix of water and aggregates (sand, stones, gravel etc)

(3) Weather Conditions, all these factors will all have effects on the concrete and mortar strengths to be achieved.

A combination of these factors will indirectly affect the quantity of cement you need for your project, types of cement needed or selected and which will inevitably affect your project costs of capital.

The information will also give you a better understanding of the cement types sold by different manufacturers, concerns about good and bad cement types, with brands such as Ghacem, Dangote, Diamond, Cimaf and more brands selection for constructional purposes. The choice and types of cement brands goes hand in hand with the cost price of the cement, and will affect your construction costs, information and knowledge on the correct mix cement and aggregates will save you money on the project costs of capital.

Cement types selection in Ghana has been a major problem for most project managers, masons, or buyers making decisions on the purchasing of cement for construction and DIY projects. In Ghana, any time a building suffers any constructional defects such as cracks, sinking, subsidence to collapse the tradesmen or house owners attribute it to the type of cement selected or used for the construction. As a result when cement selection and purchasing decisions are made, customers always make wrong choices on the types of cement selected, going in for higher grade cement or a selection based on strengths or clinker constituents, which always increases the project costs of capital unnecessarily. These constructional defects are not attributable to the type of cement used but the civil engineering methods used are some of the main causes. Find a brief discussion on some areas of civil engineering works to be considered when undertaking construction of houses.

Some factors which should be taken into consideration when undertaking the construction of a house or building, road, tunnel and more goes hand in hand with the civil engineering works, that is the ground works undertaken before the actual erection of any building or pillars. It has been found that most walls in buildings and houses in Ghana and for that matter in most West African countries suffer cracks, collapse, subsidence, sinking, sagging and water percolation due to poor civil engineering and ground works undertaken before the construction of buildings. When such defects on building happen, it is then attributed to the types or brands of cement used for the construction which is not true or established.

Incorrect reinforcement’s works, ground compaction and incorrect types of materials used has been a problem leading to some house builders trying to use different grades of cement to circumvent the poor ground works and civil engineering. Undoubtedly, you find a local mason or block layer constructing a building on clay ridden ground, water logged area without any ground stabilization methods such as ground water testing and compaction, undertaking a wrong mix of cement, water and aggregate ratio or laying block with inappropriate mortar joints (millimeters).

Some masons or local tradesment do not use concrete or cement mixers to achieve best results of aggregates, water and cement mixing and worse of all you will find them using a shovel to mix cement without a concrete mixer. Aside that you will have a mason adding too much water to cement and aggregate mix when it has been boldly written on the cement packaging by the manufacturer to add Less Water.

All these bad practices in construction lead to cracks, sagging and other subsidence problems. You do not need to use wall tiles to prevent water from sipping into walls of your building or house, the wet walls is water percolation from the groundwater into the walls. For, there are no rocks, gravel filling or compaction to provide a barrier separating ground water from the sub-structure or foundation of the building.

There is no such thing as best cement brand sold in Ghana with popular brands such as Ghacem, Cimaff, Dangote, Diamond cement and other brands. The combination of the factors listed above determines the results to be achieved from your construction works,

The strength development of cement is not only defined by the composition but also by the grinding fineness, divided into classes (32.5 – 42.5 – 52.5).

This classification takes place based on a pressure test after 28 days. Within each strength class the performances define from an early stage the distinction between the ‘Normal’ (N) and ‘Rapid’ (R) version.

The mortar prisms are based on a standard ratio of cement, water and sand. The strength indication for cement has only a limited effect on the strength of concrete or mortars to be achieved. This is because a type of concrete with among others a lower water-cement factor (the ratio of cement as opposed to water) than the type of mortar can be created, which is used for the strength classification of cement. The composition of the aggregate also has an effect on the final strength of concrete. For this reason, the strength class of cement cannot be traced back to a maximum strength class for concrete or mortar.

Class 32.5 is indicated for applications where a high initial strength is not required, at average ambient temperatures (10 – 15°C) and with constructions of standard thicknesses (< 50 cm).

Cements with strength class 42.5 are mostly used in the event that the required compressive strength of concrete at 28 days must exceed 30 N/mm² (i.e. higher than class C25/30 according to NBN B 15-001). These cements are also suitable for use at lower temperatures.

Class 52.5 is used for applications where an even higher initial strength than class 42.5 is required. E.g. for the rapid stripping of prefabricated elements.

Cement Types

Cement production is a combination of mix of clinker and fly ash or slag which is compressed and baked at high temperatures of around 800c to 1000c degrees and goes through a lot of processing to achieve the final mix of cement. Each cement manufacturer has the methods used for the mix of the different constituents for the production of cement.

There are a number of different cement types, referred to as CEM I up to and including CEM V, with a smaller or larger content of Portland Clinker (is a byproduct of cement) and slag or fly ash.

  • CEM I: Portland cement with a maximum of 5% other materials.
  • CEM II: all kind of hybrids of Portland cement with for example slate, fly ash, slag… minimum 65% Portland cement.
  • CEM III: blast furnace/Portland cement mixture in 3 classes: A, B and C; whereby CEM III/A contains the least (40%) and CEM III/C contains the most (90%) slag.
  • CEM IV: Pozzolana cement varieties
  • CEM V: composite cements, with mixtures of Portland cement, slag and Pozzolana.

Cement types are indicated by CEM followed by the number of the main sort in Roman numerals. After this there follows a forward slash with following the letters A, B or C (= decreasing clinker content). The indication can be followed by a horizontal slash and a capital letter to indicate which component is used in addition to the Portland cement clinker.

The conclusion is that the above research into cement and selection depends on the types of mortar and concrete strength to be achieved. At Dansoaa we have in house qualified civil engineers  architects,  quantity surveyors  and project managers whom you can consult on most aspect of construction and building materials and hardware sourcing.

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