IOSR Journal of Engineering (IOSR-JEN) Volume 5 Issue 5 Version 2

2018

The study investigated potentials of rice husk ash as a replacement for Ordinary Portland Cement in the production of Compressed Earth Block (CEB) with a view to reducing building construction cost and the embodied energy of the blocks in the context of Nigeria. Graded levels (i.e. 10, 20, 30 and 40%) of RHA replaced cement in the mix for CEB moulding. The results of X-ray diffraction showed that RHA contained 80% SiO2. Also, the results of the compressive strength, water absorption capacity, and bulk density testing indicated that low compressive strength, high water absorption capacity, and low bulk density exhibited by RHA-CEB make doubtful the suitability of RHA as a partial replacement for Ordinary Portland cement in the building construction in the wet regions. However, RHA could find useful application as a stabilizing agent in CEB rather than as a partial replacement of cement.

Journal of Engineering and Technology, 2011

Sandcrete blocks have been in used in many nations of the world including Nigeria, playing a major role in the building industry. The material constituents, their mix, presence of admixtures and the manufacturing process are important factors that determine the properties of sandcrete blocks. This paper investigates the effects of a partial replacement of cement with rice husk ash (RHA) on some engineering properties of hollow sandcrete blocks with 1:6 cement-sand mix ratios. Single block size 225 x 225 x 450 mm, is produced with a vibrating machine. Results show that the addition of RHA produces blocks of lower density. Particularly, the density of the blocks decreases as the RHA content increases. The compressive strength of the block is also not enhanced. Results also reveal that the thermal and hygrothermal properties of the blocks are significantly affected.

Advances in Science and Technology Research Journal

This paper presents the outcome of a research study aimed at the performance evaluation of rice husk ash as partial replacement of cement in sandcrete blocks used as masonry units. Rice husk from the rice cultivated in the North of Pakistan was used in the study. It was first combusted in a locally manufactured incinerator to convert it into rice husk ash (RHA) and then finely ground to powder form for use with cement. Blocks with the size of 305×203×152 mm were molded with 0, 10, 30, 40 and 50% replacement of cement with RHA to find compressive strength at 3, 7, 14 and 28 days age of curing. The results showed that water requirement for the required workability of the sandcrete increased along with the RHA content, whereas the compressive strength decreased with increase in RHA content. However, the comparison of compressive strengths of RHA sandcrete blocks with the strength of commercial concrete blocks available in the market and used as masonry units in Pakistan showed that sandcrete blocks having the sand to binder ratio of 1:8 and using up to 40% of RHA as replacement of cement gave larger compressive strength than that of commercial concrete blocks and only marginally lower strength for 50% replacement.

The production of sandcrete blocks using groundnut shell ash (GSA) as cement replacement was investigated. Six number sandcrete blocks were cast for each replacement levels (0, 10,20,30,40, and 50 percentage) with GSA. The blocks were cured and crushed at 7, 14, 21, and 28 days. The results show that the compressive strength ranges from 4.50 N/mm 2 to 0.26N/mm 2 .The optimum replacement level was achieved at 20% with a corresponding strength of 3.58 N/mm 2 . The strength at the optimum level was within the recommended limit of the Nigerian Industrial Standard (NIS) 87:2000. The results also showed that the strength decreases with increase of cement above 20% replacement. It was also observed that in the chemical composition of the GSA as compared to cement, the amount of K2O was higher in GSA and also CaO was less than what is obtained in cement.

This work investigated the compressive strength of binary and ternary blended cementsandcrete and soilcreteblocks containing coconut huskash (CHA) and oil palm bunch ash (OPBA). 135 solid sandcrete blocks and 135 solid soilcrete blocks of 450mm x 225mm x 125mm were produced with OPC-CHAbinary blended cement, 135with OPC-OPBAbinary blended cement, and 135with OPC-CHA-OPBAternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%.Three sandcrete blocks and three soilcreteblocks for each OPC-pozzolan mix and the control were crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, 90, 120, and 150 days of curing. Binary and ternary blended cement sandcrete and soilcrete block strength values were found to be higher than the control values beyond 90 days of hydration at 5-25% OPC replacement with pozzolan. The 150-day strength values for OPC-CHA-OPBA ternary blended cement sandcreteand soilcrete blocks were respectively 6.00N/mm 2 and 5.30N/mm 2 for 5% replacement, 5.90N/mm 2 and 5.20N/mm 2 for 10% replacement, 5.75N/mm 2 and 5.10N/mm 2 for 15% replacement, 5.70N/mm 2 and 5.00N/mm 2 for 20% replacement, and 5.50N/mm 2 and 4.90N/mm 2 for 25% replacement; while the control values were 5.20N/mm 2 and 4.80N/mm 2. Thus, OPC-CHA and OPC-OPBA binary blended cements as well as OPC-CHA-OPBA ternary blended cement could be used in producing sandcrete and soilcreteblocks with sufficient strength for use in building and minor civil engineering works where the need for high early strength is not a critical factor. Keywords: Binary blended cement, coconut husk ash, oil palm bunch ash, pozzolan, sandcrete block, soilcrete block, ternary blended cement. ___________________________________________________________________________ INTRODUCTION Sandcrete and soilcrete blocks are cement composites commonly used as walling units in buildings all over South Eastern Nigeria and many other parts of Africa. The major constituents of sandcrete are water, cement, and sand. Its essential difference with soilcrete is that natural soil, notably laterite, is used in soilcrete making rather than sand. Many researchers have investigated various aspects of these important construction materials. Joshua and Lawal (2011) successfully replaced sand with laterite in suitable optimal percentages to produce laterizedsandcrete blocks with adequate strength and more cost effectiveness than the traditional sandcrete blocks. Mama and Osadebe (2011) developed a mathematical model for optimizing the strength of laterizedsandcrete blocks.Baiden and Tuuli (2004) confirmed that mix ratio, materials quality, and mixing of the constituent materials affect the quality of sandcrete blocks.Wenapereand Ephraim (2009) found that the compressive strength of sandcrete blocks increased with age of curing for all mixes tested at the water-cement ratio of 0.5. Their findings showed that the strength at ages 7, 14, and 21 days were 43%, 75%, and 92% of the 28-day

2017

1Lecturer, Department of Building, University of Jos, Nigeria 2Lecturer, Department of Building, University of Jos, Nigeria ---------------------------------------------------------------------***--------------------------------------------------------------------Abstract – This research is aimed at determining the suitability of millet hush ash (MHA) as partial replacement of cement in the production of sandcrete blocks. This study examined the physical and chemical properties of locally sourced millet husk ash as a pozzolana. Mix ratio 1:6 (cement: sand) was used in this study for sandcrete block production. Cement was partially replaced with MHA in varying percentages of 0, 10, 20, 30 and 40% by weight. The blocks were molded and cured for 7, 14 and 28 days. The compressive strengths of the blocks were determined at 7, 14 and 28 days by crushing using compressive strength testing machine. The result of the chemical analysis of the locally sourced millet husk ash showed that it is...

Prompted by the high cost of building materials as well as the amount of dead load weight generated by block wall on beams and columns in partitioning works most especially in high rise buildings, this project work on the use of sawdust as admixture in production of hollow sandcrete blocks was carried out in order to investigate a possible solution to the problems. The research work understudies the weight vis-a-vis cost of production of available commercial sandcrete blocks in Lagos metropolis. It has been observed that prices of construction blocks were typically above the reach of many Nigerians. Production of sandcrete blocks were made by partial replacement of sand with a varying proportion (10%, 20%, 30% and 40%) of sawdust. The strength of each block was determined to ascertain conformity with the minimum acceptable standards. Equally, the weights were checked and compared with blocks devoid of sawdust. The tests were carried out on the 7, 14, 21 and 28 days after production. From data gathered, recommendations were given which will be beneficial to the construction industry and general populace in respect of low cost and light weight sandcrete blocks. It is concluded that if the recommendations herein should be followed, problems of cost and weight in building construction shall be reduced.

This work investigated the compressive strength of binary and ternary blended cementsandcrete and soilcreteblocks containing sawdust ash (SDA) and pawpaw leaf ash (PPLA). 135 solid sandcrete blocks and 135 solid soilcrete blocks of 450mm x 225mm x 125mm were produced with OPC-SDAbinary blended cement, 135with OPC-PPLAbinary blended cement, and 135with OPC-SDA-PPLAternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%.Three sandcrete blocks and three soilcreteblocks for each OPC-pozzolan mix and the control were crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, 90, 120, and 150 days of curing.Binary and ternary blended cementsandcrete and soilcrete block strength values were found to be higher than the control values beyond 90 days of hydration at 5-20% OPC replacement with pozzolan. The 150-day strength values for OPC-SDA-PPLA ternary blended cement sandcreteand soilcrete blocks were respectively 6.00N/mm 2 and 5.20N/mm 2 for 5% replacement, 5.90N/mm 2 and 5.10N/mm 2 for 10% replacement, 5.75N/mm 2 and 5.00N/mm 2 for 15% replacement, and 5.70N/mm 2 and 4.90N/mm 2 for 20% replacement; while the control values were 5.20N/mm 2 and 4.80N/mm 2. Thus, OPC-SDA and OPC-PPLA binary blended cements as well as OPC-SDA-PPLA ternary blended cement could be used in producing sandcrete and soilcreteblocks with sufficient strength for use in building and minor civil engineering works where the need for high early strength is not a critical factor.

The study investigates the compressive strength properties of sandcrete blocks produced within the Calabar metropolis. Ten blocks moulding sites were visited and twelve sandcrete blocks were randomly selected from each site, and cured for 3, 7, 14 and 28 days respectively. The aggregates used for the moulding of the blocks were also collected and their particle sizes analysed. The results show that the 28-day compressive strengths of sandcrete blocks produced in Calabar block industry range between 0.23N/mm 2 and 0.58N/mm 2 . These are below the minimum requirements of 1.75N/mm 2 by the Nigerian National Building Code for individual block, and 2.0N/mm 2 by the British Standard for non-load bearing walls.

Open Journal of Civil Engineering, 2020

The cost of cement has made concrete production expensive such that the housing deficit in developing countries is on the rise despite all the efforts by governments and other stakeholders to produce affordable housing units for the populace. Ashes of agricultural products such as rice husk, known as mineral admixtures may have pozzolanic characteristics which would be more beneficial to the housing industry in terms of strength gain and economy than being pollutants to the environment. Rice Husk Ash (RHA), because of its finely divided form and very high silica content and amorphousness, proved to be useful for strength gain of Rice Husk Ash Concrete (RHAC). Rice husk ash was manufactured by uncontrolled burning, ground, sieved and replaced with cement at 0%, 5%, 10%, 15%, 20% and 25% in mass for the mixes C20, C25, C30 and C35 where their compressive strengths were verified at 3, 7, 14, 21, 28, 56, 90 and 180 days. The X-ray diffraction pattern list indicated amorphous as well as diffused peak of about 8000 counts of SiO 2 representing crystalline structures identified as cristobalite. A physical examination of the RHA showed very fine appearance, grey color and specific gravity of 2.06. The chemical analysis also revealed the existence of oxide content to be 55.8% representing 0.78% of Fe 2 O 3 , 54% of SiO 2 and 1.06% of Al 2 O 3 representing 20.23% lower than the minimum value of 70% required for pozzolans. Generally, the compressive strength values decreased as the RHA content in the mixes increased but when compared to the control concrete the optimum replacement percentage of Ordinary Portland Cement (OPC) with RHA at 5% showed an increase above the control concrete for C20 mix. The increase in the RHA in the mixes resulted in the high demand for water in all the mixes.