Comparison of locally excavated sand with river sand in terms of strength in sandcrete blocks

Project Abstract

The construction industry heavily relies on sand as a key ingredient in the production of concrete blocks. River sand has been traditionally used for this purpose, but concerns over environmental impact and depletion of river sand sources have led to a search for alternative sources. Locally excavated sand has emerged as a potential substitute for river sand in the production of sandcrete blocks. This study aims to compare the strength characteristics of sandcrete blocks produced using locally excavated sand versus river sand. The research involved obtaining samples of both locally excavated sand and river sand for laboratory analysis. The sand samples were tested for properties such as grain size distribution, specific gravity, and fineness modulus. Sandcrete blocks were then produced using a mix ratio of 16 (cement to sand) by volume for both types of sand. Compressive strength tests were conducted on the sandcrete blocks at various curing periods to evaluate their strength performance. The results of the study indicated that the locally excavated sand met the requirements for use in sandcrete block production based on standard specifications. The grain size distribution, specific gravity, and fineness modulus of the locally excavated sand were found to be comparable to those of river sand. In terms of compressive strength, the sandcrete blocks made with locally excavated sand exhibited similar or even higher strengths compared to those made with river sand. The findings suggest that locally excavated sand can be a viable alternative to river sand in the production of sandcrete blocks. Not only does it offer a sustainable option by utilizing local resources, but it also demonstrates good strength performance. This could potentially reduce the dependency on river sand, which is often sourced through environmentally damaging practices like dredging. Utilizing locally excavated sand could also lead to cost savings and reduced transportation expenses. Overall, the study provides valuable insights into the use of locally excavated sand as a substitute for river sand in sandcrete block production. Further research could delve into optimizing mix ratios, exploring different curing methods, and investigating the long-term durability of sandcrete blocks made with locally excavated sand. This research contributes to the sustainable development of the construction industry by promoting the use of alternative materials that are both environmentally friendly and structurally sound.

Project Overview

<p> </p><p>INTRODUCTION</p><p>This research work means to determine the different properties of sandcastle blocks moulded with a locally excavated sand, in terms of compressive strength, durability and cost and economic importance, and that of River Sand. And after, compare the two strengths of the sandcrete which will help in recommending the right give the desired strength for the designed strength for a particular purpose.</p><p>NSUDE as case study, Nsude is in Udi, Enugu west, Enugu State.</p><p>1.1 BACKGROUND OF THE STUDY</p><p>Sandcrete is a yellow-white building material made from a binder (Portland cement), sand in a ratio of circa 1:8, and water. Sometime other ingredients may be added to reduce the amount of Portland cement such as “pozzolanas and rice husk ash”. Sandcrete is similar but weaker than mortan for which the ratio is 1:5.</p><p>Sandcrete is usually used as hollow rectangular blocks similar to concrete masonry units, often 45cm (18”) wide, 15cm (5.9”) thick and 30cm (12”) with hollows that run from top to bottom and occupy around one third of the volume of the block.</p><p>1.2 STRENGTH AND USAGE</p><p>The final compressive strength of sandcrete can be as high as 4.6N/mm2 which is much less than concrete’s 40N/mm2. Sandcrete is unsuitable for load-bearing columns, and is mainly used for</p><p>walling of a house</p><p>– &nbsp; &nbsp; making a fence</p><p>– &nbsp; &nbsp; Septic tank and soak away tank’s</p><p>– &nbsp; &nbsp; Building a generator’s house.</p><p>In Nigeria, measured strength of commercial available sandcrete blocks was found to be between 0.5 and 1N/mm2, which is well below the 3.5N/mm2 that is legally required. This development may be due to the need of the manufacturers to keep the price low, and since the main cost-factor is the Portland cement, they reduce that, which results in a block that starts behaving more like loose sand.</p><p>1.3 SANDCRETE BLOCK SIZES</p><p>They are many different types of blocks used in modern building, they include:</p><ul><li>9” hollow blocks (450mmx225mmx225mm)</li><li>6” hollow blocks (450mmx150mmx225mm)</li><li>6” solid blocks (450mmx150mmx225mm)</li><li>5” solid blocks (450mmx125mmx225mm)</li><li>9” solid blocks (450mmx225mmx225mm)</li></ul><p>1.4 CONSTITUENT MATERIALS OF SANDCRETE BLOCKS</p><p>These include cement, fine aggregate (sharp sand) and water.</p><p>1.4.1 CEMENT</p><p>This refers to any adhesive and the material used in connection with block and it is referred to as “hydraulic cement” because the setting and hardening depends on the preserve of water. The cement widely used in civil work is called “Ordinary Portland Cement”.</p><p>1.4.2 &nbsp; &nbsp; FINE AGGREGATE</p><p>The two major types of sand used are white and coloured sand. The sand were not free from materials such as dust, silt, tree roots etc. The sources of sand include pits, rivers and sea.</p><p>1.4.3 &nbsp; &nbsp; WATER</p><p>Any type of water available can be used to mould sandcrete blocks. This includes water from stream, rivers, boreholes etc.</p><p>1.5 STATEMENT OF THE PROBLEM</p><p>Apart from bad mixing ratios, which happen even some sandcrete blocksproducers add more yield of blocks, some other things can cause blocks to be in bad condition which can affect the quality of the sandcrete produced.</p><p>1.5.1 &nbsp; &nbsp; USING OF BAD CEMENT</p><p>Due to the prevailingadverse economic conditions, some sandcrete block makers tend to go for very cheap cement which may not have the required quality to bind a solid block. These block break soon after they are made. Some cement sellers who had cement keptin stock for so long sell it at give away price to the sandcrete block makers if the notice that the quality of the cement has detoriated.</p><p>1.5.2 RE-BAG CEMENT</p><p>Another thing to note with cement is that some cement sellers re-bag cement, removing some quantity of cement or put low quality cement product in a bag of a high quality and trust cement brand. Theration you thought you are using to produce a given quality has been compromised and it will produce a low quality block that can easily break even before it is being used for the project.</p><p>1.6 THE OBJECTIVE OF THE STUDY</p><ul><li>This project research will help us to understand the different strength of sandcrete blocks produced with locally excavated sand and River sand.</li><li>This will also help to know the properties of Nsude sand after laboratory test has been carried out.</li><li>This will help us in determining the moulding methods and properties of sandcrete blocks. These properties are determined by the ratio of block constituents such as cement, water and sand.</li></ul><p>1.7 SCOPE OF THE STUDY</p><p>The scope of this project work is limited to obtaining the comparison of locally excavated sand with River sand in terms of strength in sandcrete blocks.(Nsude as case study).</p><p>1.8 SIGNIFICANCE OF THE STUDY</p><ol><li>To help us understand the strength of sandcrete blocks produced with locally excavated sand and River sand in Nsude.</li><li>To help us determine the properties of Nsude sand after carrying out laboratory test.</li></ol> <br><p></p>