Cost Efficient Construction Lecture Notes 2022 PDF

College of Engineering and Technology Department of Construction Technology and Management Cost Efficient Construction Chapter 4: Cost Efficient Building Materials By: Simachew 1B.  4.1. Introduction Buildi...

College of Engineering and Technology Department of Construction Technology and Management Cost Efficient Construction Chapter 4: Cost Efficient Building Materials By: Simachew 1B.  4.1. Introduction Building materials account for 60 to 65% of the cost of housing const ruction. The leading modern (conventional) building materials are: cement, co ncrete, steel, bricks and others, but many people cannot afford them due to a constant rise in cost. This calls for wide spread technology dissemination and avail ability at decentralized locations of cost-effective building mat erials and construction techniques. WKU, Cost Efficient Construction, Lectu 2 re Notes, 2022, BY:- Simachew B  Low cost building Materials Low cost building Materials are:  Not sub-standard  The materials are available locally:- Reduced transportation cost, use of locally available labor/workmanship.  Manufactured by applying civil engineering know-how for b etter service and economy. WKU, Cost Efficient Construction, Lectu 3 re Notes, 2022, BY:- Simachew B  Cont.. - Serve the basic need of th Traditional e majority of the people. - Modification in the production pro cess and application technique is ne Low cost building eded:- For better structural and funct materials ional acceptance. - Obtained by using Conventional modern technologies -Are fruits of research4 WKU, Cost Efficient Construction, Lectu re Notes, 2022, BY:- Simachew B  Selection of Low Cost Building Materials for Low Cost Housing (Eg. Condominium) The first step is to select eco-friendly building materials. This also e nhances the sustainable design principle. Low cost housing can be defined as It should consider the criteria. provision of housi ng which caters to the minimum requi rements of masses within their incom e capabilities, with out sacrificing qua lity of the construc tion. WKU, Cost Efficient Construction, Lectu 5 re Notes, 2022, BY:- Simachew B  4.2. Alternative Construction Materials 1) Mud 2) Cement and concrete substitute 3) Wood 4) Wall materials - mud , Sun-dried bricks, Rammed earth, -Stabilized soil blocks , Kiln-burnt bricks - Timber/bamboo, agrostone - Stone block masonry - Precast/factory-made walling units using light weight cellular concrete - Concrete hollow blocks - Ferro-cement:-The term is most commonly applied to a mixture of Portland cement a nd sand applied over layers of woven or expanded steel mesh and closely spaced sma ll-diameter steel rods. WKU, Cost Efficient Construction, Lectu 6 re Notes, 2022, BY:- Simachew B Application of Ferro-cement Housing application Agricultural/hydraulic structure Marine application WKU, Cost Efficient Construction, Lectu 7 re Notes, 2022, BY:- Simachew B  Cont.. 6) Interlocking blocks 5) Doors and windows 7) Concrete blocks Timber 8) Bamboo Steel framed 9) Other pre-cast elements Ferro-cement -Thin pre-cast lintels Magnesium board -Pre-cast septic tanks Cement particle board -Ferro-cement bio-gas units Pre-cast hollow blocks -Pre-cast poles for street lighting -Ferro-cement water tanks WKU, Cost Efficient Construction, Lectu 8 re Notes, 2022, BY:- Simachew B  1. Mud Main techniques using earth as a building material In fact there are 12 main techniques of using earth as a construction material are recognized; (ad obe, rammed earth, CEB, straw clay, extruded earth …….) From those techniques; nowadays adobe, rammed earth, and compressed earth block are the mo st widespread and have reached extremely high scientific and technological levels.  Merit of mud  Environmentally friendly  Cool in summer and warm in winter  Available everywhere in abundance  Demerit of mud  Temporary in nature  Prone to erosion by heavy rain WKU, Cost Efficient Construction, Lectu 9 re Notes, 2022, BY:- Simachew B  Cont.. Improvement of mud By using suitable design and construction techniques (Ramming); By adding cement, lime, bitumen or fibers its strength can be increase d and can also became water resistant; 3 -10 % cement stabilized blocks are better than adobe mud bricks A. Adobe Blocks: often improved by additi on of straw/grass/ or other fibers. is molded in to a brick form and dried in the sun. WKU, Cost Efficient Construction, Lectu 10 re Notes, 2022, BY:- Simachew B  History of adobe brick “Adobe” is the Spanish name derived from the older Arabic "al-tob", dating from t he Moorish occupation of Spain. The earth, in a malleable state, often improved by addition of straw/grass/ or other fi bers, is molded in to a brick form and dried in the sun. There has been a lot of research on this technique with the result, that rational engine ering solutions can now be applied to structures in Adobe bricks. Today Adobe brick construction has been partially adapted to economical, social an d technical changes. WKU, Cost Efficient Construction, Lectu 11 re Notes, 2022, BY:- Simachew B Clay adobe block production near Jimma WKU, Cost Efficient Construction, Lectu 12 re Notes, 2022, BY:- Simachew B Adobe construction in Addis WKU, Cost Efficient Construction, Lectu 13 re Notes, 2022, BY:- Simachew B  Cont.. WKU, Cost Efficient Construction, Lectu 14 re Notes, 2022, BY:- Simachew B B. Rammed earth Ramming steps Rammed earth: The earth is mass ively dumped into formworks, compacted by means of a ram mer, layer by layer, and finally formwork is removed. Rammers:  Manual rammers consist of a wooden or steel rod with a heavy wooden or me tal striking head. The heavier it is, the better the compaction, but the more tiring for the user. WKU, Cost Efficient Construction, Lectu 15 re Notes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lectu 16 re Notes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lectu 17 re Notes, 2022, BY:- Simachew B  Conti… WKU, Cost Efficient Construction, Lectu 18 re Notes, 2022, BY:- Simachew B  C. Compressed Earth Block (CEB)  A compressed earth block (CEB) or stabilized compressed soil blocks (SCSB) a re earthen bricks produced using a machine that either manually or mechanically compresses the soil into a mould.  The basic material, required to manufacture compressed stabilized earth buildin g blocks is a soil containing a minimum quantity of silt and clay so as to facilitat e cohesion.  Sand/fine gravel: 40 - 75%  Silt: 10 - 30%  Clay: 15 - 30% A suitable soil should not contain organic material or excessive soluble salts. WKU, Cost Efficient Construction, Lecture N 19 otes, 2022, BY:- Simachew B  Cont.. WKU, Cost Efficient Construction, Lecture N 20 otes, 2022, BY:- Simachew B  Soil Stabilization  Soil stabilization is the process of improving the strength paramete rs of soil and thus increasing the bearing capacity of soil. WKU, Cost Efficient Construction, Lecture N 21 otes, 2022, BY:- Simachew B  Cont.. From many stabilizers cement and lime are the most common ones. The selection of a stabilizers is depend upon the soil quality and the p roject requirements. Cement will be preferable for sandy soils and to achieve quickly a hig her strength. Lime used for very clay soil, but will take a longer time to harden and to give strong blocks. The average stabilizer proportion is rather low: Minimum Average Maximum Cement stabilization 3% 5% No technical max. Lime stabilization 2% 6% 10% WKU, Cost Efficient Construction, Lecture N 22 These low %tage are part of the cost effectiveness of CSEB otes, 2022, BY:- Simachew B  Cont..  Procedure for making compressed stabilized earth blocks (CSEB) Collect the soil sample; Test for soil classification; Various mixing of ingredients/stabilizers with clay soil and sandy varies in %tage of mixing; The various mixes are placed in a proposed brick mold; The mold is compressed in a process (manually compress); Then it is dried for 28days; Strength determination on UTM/CTM. WKU, Cost Efficient Construction, Lecture N 23 otes, 2022, BY:- Simachew B  I. Cement Stabilization Cement stabilization in combination with densification gives soil bot h wet strength and erosion resistance. Densification or compaction reduces the soils permeability and enha nces the cementitious bonding mechanism. Soil cement is produced by dry mixing a suitable soil with a small q uantity of cement and remixing the product with a specific quantity of water. Soil cement blocks produced with compression are denser and less p orous than sand cement. WKU, Cost Efficient Construction, Lecture N 24 otes, 2022, BY:- Simachew B  Cont.. The minimum amount of cement required to stabilize a block depen ds on:  The type of soil  The degree of compression and  The final application for the blocks. Generally the interest is to minimize the cement content to below 10 %. Given suitable conditions, blocks cement contents as low as 3% are possible. Increment of cement content increases the compressive strength and decreases the absorption capacity WKU, Cost of soil Efficient Construction, otes, 2022, BY:- Simachew B cement Lecture N block. 25 WKU, Cost Efficient Construction, Lecture N 26 otes, 2022, BY:- Simachew B Compressed Earth Block (CSEB) WKU, Cost Efficient Construction, Lecture N 27 otes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lecture N 28 otes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lecture N 29 otes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lecture N 30 otes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lecture N 31 otes, 2022, BY:- Simachew B Manual press machines WKU, Cost Efficient Construction, Lecture N 32 otes, 2022, BY:- Simachew B  4. Inter-locking Blocks Interlocking blocks further differ from conventional blocks in that the units are assembled together using geometrical features incorporated in the units without the aid of mortar Deductions from a laboratory study on masonry works carried out reveals the following co nclusions applicable to the methodology adopted and the range of parameters investigated: 1. Interlocking blocks masonry has much higher output per productive hour compared to co nventional brick/hollow block masonry. 2. Due to easier alignment facilitated by the interlocking features and the elimination of vert ical joints, a production enhancement of 80-120% and 60–90% more than conventional masonry was observed for dry-stacked masonry and thin-jointed, mortar bedded interlock ing-block masonry respectively. WKU, Cost Efficient Construction, Lectu 33 re Notes, 2022, BY:- Simachew B  5. Bamboo (Vegetable Steel)  Advantages  Highly functional and it can be easily worked upon by simple tools and machines.  Beautiful  Replanting is not necessary when harvest bamboo roots sprout up again quickly  Occurs in many sizes, grades of colors, many degrees of hardness and occupies a wide range of habitats  Have high tensile strength and very good weight to strength ratio  If properly treated and industrially processed, components made by bamboo can have a rea sonable life of 30 to 40 years  Appropriate option to partially replace materials like steel, aluminum and hard forest wood for housing applications, etc.  The Guinness Book of Records (1999) reports that some of its species constitute the world’s f astest growing plants. Some of its species grow at an incredible rate of 91 cm per day. WKU, Cost Efficient Construction, Lectu 34 re Notes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, Lectu 35 re Notes, 2022, BY:- Simachew B WKU, Cost Efficient Construction, 36 Lecture Notes, 2022, BY:- Simac