Achekev Consult

03/03/2023

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27/02/2023

Analysis of structures; The general purpose of Structural Analysis is to understand how a structure behaves under loads.

25/02/2023

TRUSS: A truss gives a stable form capable of supporting considerable external load over a large span with the component parts stressed primarily in axial tension or compression. The individual pieces intersect at truss joints, or panel points👷‍♂️👷‍♀️🏗️

05/12/2021

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27/10/2021

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19/10/2021

18/08/2021

What makes good concrete?...(part 2).
In the recent post, we looked at long-term requirements of concrete. We will now examine the short-term.
Short-term requirements mostly deal with freshly mixed concrete. These include;

1. Good Concrete has quality raw materials or ingredients used which include aggregates, cement and water. These should also be properly mixed as stated in the mix design.

2. Fresh concrete should be easily mixed, transported and placed. The measure of how easily this can be done is known as Workability. It can easily be determined through a test known as a slump test which is done on site.

3. It should be uniform throughout a given batch or between batches. It should be of a consistency so that it can fill completely the forms for which it was designed.

4. It should be compacted fully without loss of energy. Compaction has an effect on strength of concrete. It is done to eliminate voids or air bubbles with in the concrete. These have an effect on the strength of concrete if the fresh concrete dries while they are still trapped. Generally, a 1% increase in the concrete air content reduces the compressive strength of concrete by 3-5%.
Air bubbles/entrapped air can also affect the appearance in form of surface voids (tiny holes) if trapped between the formwork/moulds.
Compaction should be done well because under compaction doesn’t get rid of most of the air in concrete while over compaction leads to segregation. Poor compaction also leads to concrete defects such as honey combs.

5. Good concrete should not segregate during placing and consolidation. Segregation is defined as the separation of the cement paste and concrete from each other during placing and handling.
6. Finishing characteristics; Good concrete should have a uniform texture, color, without discoloration and can easily be finished as required.

17/08/2021

What makes good concrete?
Concrete is affected by several factors from the point of mixing, placing to finishing. It is as good as the materials used and the processes applied when working with it. Good concrete can be categorized in terms of its long-term requirements or short-term requirements.

Long term requirements of hardened concrete include strength, durability and volume stability. Compressive strength is the capacity of concrete to withstand loads before failure. It is the most common performance measure used by the engineer in designing structures.

Test results are used to determine that the concrete mixture meets the requirements of the specified strength of the job. This can be performed in a laboratory by loading several samples of cylindrical specimen or cubes in a special machine. This test is done at intervals of 7 days, 28days, 90days or as may be specified by the engineer.

Compressive strength achieved by concrete at 7 days is about 65% of the target strength and 90% at 14 days. It is calculated by dividing the maximum load applied during the test by the cross-sectional area of the specimen.

Short term requirements of Concrete deal with freshly mixed concrete. We will examine these factors in the next post.

Engage our team for advice on getting the best concrete suited for your project.

Call/WhatsApp 0779686283/07001887721

11/08/2021

Renders.

For your architectural and construction needs. Call/WhatsApp 0779 686283. Or 0700 187721

06/08/2021

Did you know water fit for human consumption(potable) is what is generally considered acceptable for use in construction processes like mixing?

Non-potable sources can also be used if there is no negative impact on the properties of the finished product
Water is normally used in manufacturing, washing, mixing and curing. Water should be clean and free from injurious amounts of oil, acids, alkalis, sugar, salts and organic matter. These elements have an effect on properties of materials like brick, stone, concrete and steel.

Besides physical inspections, other tests which can be carried out to ascertain water quality include pH value test and Limits of acidity and alkalinity.

What Kind of water are you using in your construction project? You may have to pay attention to it because it also affects the quality of your finished product.

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04/08/2021

Aggregates are normally as good as the way they are processed when mined, crushed washed and separated or blended.

Characteristics of good aggregates;
Coarse aggregates(Stones) Must be dry, clean, with uniform and predictable sizes. They should be uncoated, hard, strong, dense, free from any dangerous amounts of soft, flaky or elongated particles, salts, alkali or vegetable/organic matter

Fine aggregates should be hard, clean and gritty and also free from dangerous amounts of clay, vegetable/ organic matter, loam and any kinds of salts. A physical/visual inspection and physical is the primary method to determine some of these properties

There are also several tests used to determine the quality of your sand and stones done in a laboratory.
The most common test for determining the distribution of the particle sizes in a sample is the where the aggregates are passed through sieves of different sizes and then graded.

Flakiness and elongation tests to measure the shape characteristics and Abrasion test for Hardness can also be done.
These tests help us understand the materials, their properties and behavior when subjected to specific conditions.

For more information, advice on materials and testing for your construction project.
Call/WhatsApp 0779686283/07001887721

02/08/2021

Aggregates

Aggregates are raw materials produced from natural sources and extracted from pits and quarries. They are used with a binding element like water, cement or asphalt to form compound materials like concrete used in various types of infrastructure projects.

They Give volume, stability and resistance to wear or erosion

They are Classified as either fine and coarse depending on their size; fine aggregates being the ones with smaller size particles
Fine aggregates usually consist of sand, crushed stone and they are Normally in the form of natural river sand or manufactured sand crushed from rock/stones or a mixture of both in specified proportions. They are used for mortar and concrete especially when a smooth surface is desired.

Coarse aggregates consist of screened natural gravel or crushed rock to a determined size. These are also used as a constituent of concrete and also in roads and railway construction for load distribution. They are also used in drainage, protecting pipes, filling voids and in water filtration or sewage treatment processes.

Look out for the next post on how you can tell the aggregates for your project are good or bad.

Call/WhatsApp 0779686283/07001887721 for advice on Construction materials.