Mineral Admixtures and Lime as Stabilizer in the Manufacture of Soil Cement Blocks
Published on Feb 27, 2019
Soil cement block is a construction material which is a mix of pulverized natural soil with small amount of Portland cement and water. Portland cement is most usual stabilizer and these blocks are cost effective and energy efficient alternative materials compared to the normal burnt bricks used for construction of buildings.
Soil cement blocks are dense solid blocks compacted using a hand operated machine with a mixture of soil, cement, lime, mineral admixtures and water. After 28days of curing the stabilized soil cement blocks are used for wall construction. This blocks are bigger in volume when compared with locally available conventional burnt clay bricks. Compressive strength of the block greatly depends upon the soil composition, density of the block and percentage of stabilizer. High strength for the block can be obtained by increasing the quantity of stabilizer.
Keywords : Soil-cement, Pulverized, Portland, Stabilizer, Strength, Density, Admixtures, Materials, Grain Size, Lime, Fly ash and GGBS.
The main objective of this research study is to bring the usage of mineral admixtures and lime in present constructions as building materials and also to obtain the performance of Soil Cement Blocks with these stabilizers. Here the soil that is being used is sandy soil.
Firstly, to investigate the main constituent materials and the block production process, secondly to examine the main block properties and their performance, thirdly to make proposal as to the best course of action for improved specification, testing of SCB for the duration of their service lifetime.
To study theoretical and practical methods by which soil and cement are selected, classified and tested for SCB.
To examine the mechanical properties between cement and soil by using mineral admixtures and lime as stabilizer.
To review the concepts of durability, strength and to identify the main deterioration involved.
The methodology involved in the proposed work are summarized below:
Not every soil is suitable for earth construction and SCB in particular. Identifying the properties of a soil is essential. In concrete the binder of gravel and sand is cement, whereas in a soil, the binder is silt and clay.
Grain size distribution, to know the quantity.
Compressibility, to know the optimum moisture content (OPC)
Plasticity Characteristics, to know the quality & properties of binders.
Sieving of soil:
Soil should be dried and sieved before it can be used properly mixed with cement and compressed into blocks.
Dry mixing: Mix the soil and cement thoroughly till the presence of cement cannot be detected visually. Then suitable proportion of lime and mineral admixtures is added to stabilize the mixture.
Addition of moisture: The proportion of water should be approximately close to the optimum moisture content (OMC). The mixture must be thoroughly mixed and checked for OMC.
Power operated machine may also be used in place of hand operated machines. Here hand operated machine (Mardini) is proposed in the project for compacting soil cement into blocks of desired size 12” X 6” X 4”.
Set each blocks on edges and space the blocks far enough. After 24 hours of moulding it must be thoroughly sprinkled with water three times a day. The top of the stack of blocks
must be covered by gunny cloth to prevent evaporation of water. The soil cement blocks stabilized with cement, mineral admixtures and lime must be cured for 28 days by a gentle sprinkling of water. After completion of these process that blocks should be taken under the various tests like compressive strength, water absorption and stress-strain characteristics of the soil cement blocks.
From this experimental study on soil cement blocks prepared using lime as stabilizer, cement and mineral admixtures are used in certain proportions has clearly brought out the effectiveness of lime with cement also the admixture in improving the long-term build-up of strength better than using cement alone. Introducing fly ash helps increasing the later-age strength substantially but at some cost of early-age strength, whereas GGBS helps increasing the dry density and densification of soil takes place with increases in percentage of GGBS. Herein, the combination of lime with cement and admixtures has been found to be mutually very beneficial in imparting strength to the blocks in a much better way, because the cement has taken care of stabilizer thus these blocks are having higher compressive strength.
Using of stabilizer in combination would help in reducing their quantity in the preparation of blocks and added benefit not only reducing the cost of the blocks, but also has serious implications in terms of the reduction of energy consumed in the manufacture of blocks when done in large scale. This would also help in a sustainable growth of the society by optimizing the resources used, reduction in energy consumed and lesser pollution of the environment.
Scope For Future Work:
The following characteristics can also be considered for future experimental studies
1. Flexural strength
2. Direct tensile strength
3. Pore size and porosity of the block surface
4. Detailed study can be done on soil varying clay and sand content from different areas in India.
Project Done By Ms. Arpitha K.R., Ms. Sneha M., Ms. Kavya P.S.