Sandcrete Blocks Research Articles

Effects of tyre steel fibre reinforcement on sandcrete blocks

This study investigates the effect of tyre steel fibres on compressive strength of hollow sandcrete blocks. A total of 36 number 450mm x 225mm x 225mm hollow sandcrete blocks with 0%, 1%, 2 %, and 3% of tyre steel fibre content were produced and tested for density, compressive strength and water absorption. From the test results, the densities of blocks increase with an increases in fibres contents. As at 28 days, the density increases from 1395.20 kg/m 3 for 0% to 1425.57kg/m 3 for 3% fibre content. Also, the water absorption decreases with increases in tyre steel fibres. Furthermore, the compressive strength increases with increase in tyre steel fibres contents. At 28 days, there was an increase in compressive strength of 6%, 58% and 95% for 1%, 2% and 3% fibre contents respectively. It is concluded that addition of tyre steel fibres significantly improves the performance of hollow sandcrete blocks. http://dx.doi.org/10.4314/njt.v37i4.3

Optimization Model for Compressive Strength of Sandcrete Blocks Using Cassava Peel Ash (CPA) Blended Cement Mortar as Binder

This research work applies Scheffe’s second degree simplex theory to formulate a regression model for the optimization of the compressive strength of sandcrete blocks using cassava peel ash (CPA) blended Portland cement (OPC) as binder material for different mix ratios as multivariate functions with the proportions of the sandcrete block ingredients serving as variables. The experimental values of the compressive strength were obtained by performing destructive strength tests on the blocks after curing for 28 days, with a binder-aggregate ratio of 1:8 and water binder ratio ranging from 0.45 to 0.60, the OPC being replaced with CPA at 0 – 30% for the respective water-binder ratios. The optimization model from the Scheffe’s mixture method for a (4, 2) factor space was found to be y= f(x) = 1.95x1 (2x1-1) + 1.84x2 (2x2-1) +1.81x3 (2x3-1) +1.79x4 (2x4-1) + 6.08x1x2 + 5.72 x1x3 + 1.89 x1x4 + 7.28 x2x3 + 1.80 x2x4 + 7.16 x3x4. The model was tested using the student t- test at 95% accuracy and found to be accurate. Thus, the model can be used to predict any desired compressive strength value for CPA-OPC blended sandcrete blocks given any water-cement ratio between 0.45 and 6.0 and vice versa. Kathmandu University Journal of Science, Engineering and TechnologyVol. 13, No. 2, 2017, page:1-14

Comparative Analysis of Mono-Factorial Effects on Compressive Strength of Sandcrete Block Produced at Various Curing Age in the Warm Humid Climate of Nigeria

Quality of a composite material like sandcrete block is basically a function of the basic properties of the constituent ingredients, mix ratio relationship and its production characteristics. This study, investigate the effects of change in quantities of the constituent ingredient on compressive strength of sandcrete blocks produced at various curing ages in Owerri Metropolis. Field survey was conducted in the area to determine the production characteristics of the blocks marketed in the area. Based on the prevalent nominal mix ratio of the block, mix design on the constituent ingredients of the block based on box-wilson symmetric composite plan B3was adopted. Results of the strength from each experimental set of the design were used to formpolynomial regression models of blocks cured at various ages. Findings show that the average compressive strengths of the 7-day, 14-day, and 28-day old cured blocks are 1.578 N/mm2, 1.604 N/mm2, and 1.975 N/mm2.Mono-factorial analysis shows that at its respective age of curing, cement and water factors have stronger effect on the strength of the block than sand factor. The nature of their influences is positive, and more linear than quadratic and mutual interaction relationships. The relationship of mutual interaction between the cement and water factors is seen only in the models of the 7-day and 28-day curing ages in the study. Since the strength of the block increases with increase in the age of curing, it therefore confirms the standard practice of 28-day curing age for improved quality of sandcrete block in the industry; as well as recommending mono-factorial analyses on the effects of the independent factors of the mix designed blocks cured age 28-day age, towards optimum composition of the sandcrete mix ingredients for the desired quality of the blocks produced in the study area.

The effect of crushed plastics waste on the structural properties of sandcrete blocks

The need for proper disposal of plastic waste has prompted researchers to consider the best way of recycling this non-biodegradable material. This research has looked into the production of sandcrete blocks, using shredded waste plastic in replacing fine aggregate at 0%, 5%, 10%, 15%, 20% and 100%. The laboratory experiments conducted were: compressive strength, flexural strength, density and water absorption tests. Both the compressive and flexural tests revealed that sandcrete blocks that contains 5% partial replacement of fine aggregate with shredded plastic have the highest strength when compared with other mixes, the density and water absorption test showed that the control sample has the best result. The study concluded that plastic waste can be used to partially replace fine aggregate in sandcrete block at not more than 5%.

Partial Replacement of Cement with Coconut Shell Ash in Sandcrete Block

In this study, Coconut Shell Ash (CSA) has been used to partially replace cement in Sandcrete Block (SB) manufacture in order to determine the quality of the SB produced in terms of compressive strength and durability. CSA has pozzolanic properties and as such, could serve as a partial replacement for cement and thus offset the cost of SB production. Laboratory tests were conducted to determine some engineering properties of the SB including compressive strength, water absorption, sorptivity and average density of SB with 0%, 10%, 15%, 20% and 25% cement replacement. The compressive strength was measured for 3, 14 and 28 day curing period. Results obtained clearly showed that increase in percentage of CSA in the mix produced SB of lower density, sorptivity and water absorption. Also, compressive strength of the SB increased at 10% replacement by 9% and 16% for SB of end-web to center-web ratios of 1:1 and 1:2 respectively. In addition, it was observed that the compressive strength of the SB only improved after 28 days curing. The SB produced in the course of this research is more resistant to ingress of moisture and suitable for walling in areas where surface and ground water impacts are significant and also in applications where light weight walls are desirable.

Correlates of Peri-Urban Architecture in Ibadan, Nigeria

Peri-urban architecture refers to the architecture that has both urban and rural characteristics. In Nigeria, housing is daily becoming a mirage for the generality of the people in the urban areas, while the peri-urban area is developing rapidly. This paper therefore, assesses the correlates of Peri-urban architecture in Ibadan, Southwest, Nigeria. A total of 2,646 Questionnaires were administered to house owners through multi-stage sampling technique which was complemented with field observation. Both descriptive and inferential statistical analyses were employed in the presentation of the findings; Multiple Analysis of Variance (MANOVA) was used to analyse the relationship between socio-economic characteristics of house owners measured by gender (X,), religion (X,), educational background (X,) and employment status (X,), while peri-urban architecture was depicted by wall materials characterised by sandcrete block (Y,), mud (Y,) and brick (Y,). Most of the respondents (51.7%) practiced Christianity, while 65.7% were male. Also, 35.0% had HND/1°/ Postgraduate degree and 10.4% were self-employed. The significant house types in the area were flat bungalow (38.9%) and Brazilian bungalow (37.9%); 40.6% houses were uncompleted and inhabited. MANOVA shows a significant relationship between sandcrete block and educational background (X,) with p=0.0000 Thus, educational background of respondents determined the utilisation of sandcrete block as walling material; house owners that used sandcrete block had HND/1°/ Postgraduate degree. Also, employment status played significant roles in the choice of mud material with p=0.0000 and respondents that were unemployed stay in mud houses more than any other socio-economic groups. The study suggests that, government should subsidize cost of building materials as well as encourage the use of alternative building materials so as to ease housing problems.

Quality assessment of sandcrete blocks produced in Adeta, Kwara State, Nigeria

The durability of a building is determined to a great extent by the quality of materials used in its construction. Sandcrete block is a major building material in Nigeria. This research assessed the quality of blocks produced in Adeta, Ilorin West Local Government Area of Kwara State, Nigeria. Eight block factories were selected from the study area and the quality of their blocks were measured for their water absorption ratios and compressive strengths and compared with the Nigerian Industrial Standards (NIS) specifications. Six samples each of size 450mm x 225mm x 225mm per factory were tested. Experimental findings revealed that the absorption rate of the sandcrete blocks were higher than the 12% specification. The compressive strengths of the blocks which ranges from 0.19N/mm2 to 0.40N/mm2 fall below the minimum specification of 2.5N/mm2. Inadequate mix ratio is a factor that resulted in the poor quality sandcrete blocks produced in the area.

Opportunities for improved sustainability in house building: The case of Dar es Salaam

The combination of a growing population and economic development in Africa will form strong drivers for building growth. Buildings drive energy consumption and carbon emissions. On the material side, cement is the driver for cost and carbon emissions. A cement productivity index is proposed. Results from a case study in Dar es Salaam show that cement is poorly used in the main application of sandcrete blocks. The relative cement productivity is < 30% compared to ordinary concrete. The main problem is the design of the blocks. Mostly, only some 5% of cement by weight is used. However, the sand matrix often needs up to 10% of water for good compaction. This means that the w/c ratio is always high in the mixes, which leads to low cement productivity. One first step could be going from solid to hollow blocks, which would enable increasing the cement content and improving cement productivity up to 50% of the defined benchmark. However, there is resistance to hollow blocks in the market. Alternative solutions, such as soil-stabilized earth, should also be looked into. For realizing the full cement strength potential, other affordable concrete solutions need to be developed for the market.

Effect of Sugarcane Bagasse Ash on the Engineering Properties of Blended Sandcrete Blocks

Effect of Sugarcane Bagasse Ash on the Engineering Properties of Blended Sandcrete Blocks

Assessment of the Mechanical Properties of Some Selected Sandcrete Hollow Blocks in Kogi State

The current wave of the collapse of building structure all over Nigeria necessitates the need to carry out research on the mechanical properties of sandcrete hollow blocks. This study looks into the quality of blocks produced by block industries in Kogi state, Nigeria to ascertain its water absorption ratio, compressive strength and sieve analysis. In order to clarify these problems, the study is directed towards testing the strength properties of commercially produced sandcrete blocks; to verify whether the sandcrete block can be improved to achieve good quality in the building industries. A Total of five block industries were visited and twenty samples were picked at random from each of the selected block industry and also, soil samples obtained for soil tests in the laboratory. The analysis of results obtained was compared with the Nigerian Industrial Standard (NIS). The average water absorption rate of the sandcrete blocks for block industry D was found to be 12.5% higher than the 12% maximum requirement of the [9]. The average compressive strength values of the sandcrete blocks range between 0.64N/mm2 and 0.87N/mm2 which when compared with standard, was found to be below the minimum requirement of the [9]. Inadequate mix ratio was observed to be one of the factors of poor quality sandcrete block production in this area. The study recommends compliance monitoring by the various regulatory body to ensure good quality of sandcrete block production.

Assessment of the Mechanical Properties of Some Selected Sandcrete Hollow Blocks in Kogi State

The current wave of the collapse of building structure all over Nigeria necessitates the need to carry out research on the mechanical properties of sandcrete hollow blocks. This study looks into the quality of blocks produced by block industries in Kogi state, Nigeria to ascertain its water absorption ratio, compressive strength and sieve analysis. In order to clarify these problems, the study is directed towards testing the strength properties of commercially produced sandcrete blocks; to verify whether the sandcrete block can be improved to achieve good quality in the building industries. A Total of five block industries were visited and twenty samples were picked at random from each of the selected block industry and also, soil samples obtained for soil tests in the laboratory. The analysis of results obtained was compared with the Nigerian Industrial Standard (NIS). The average water absorption rate of the sandcrete blocks for block industry D was found to be 12.5% higher than the 12% maximum requirement of the [9]. The average compressive strength values of the sandcrete blocks range between 0.64N/mm2 and 0.87N/mm2 which when compared with standard, was found to be below the minimum requirement of the [9]. Inadequate mix ratio was observed to be one of the factors of poor quality sandcrete block production in this area. The study recommends compliance monitoring by the various regulatory body to ensure good quality of sandcrete block production.

Models for predicting compressive strength and water absorption of laterite-quarry dust cement block using mixture experiment

The use of laterite, quarry dust and recycle aggregates etc as replacement for sand in sandcrete block production is common trend in developing countries like Nigeria. Most resources and research efforts are committed towards conducting trial test with a view to coming up with mix production that will yield the desired property. This work presents a mathematical model for predicting the compressive strength and water absorption of laterite-quarry dust cement block using augmented Scheffe's simplex lattice design. The statistical models developed can predict the mix proportion that will yield the desired property. The models were tested for lack of fit and found to be adequate. Keywords : compressive strength, laterite, mixture experiment, quarry dust, water absorption

Effects of Glass Wool Fibre on the Strength Properties of Hollow Sandcrete Block

Effects of Glass Wool Fibre on the Strength Properties of Hollow Sandcrete Block

Effectiveness of locust bean pod solution (LBPS) in the production of sandcrete blocks for buildings

Locust beam pod solution (LBPS) was prepared by extraction from the outer leathery cover of the pod soaked in water for twenty four hours in ten different concentrations of known weight of dried locust bean pod cover in 20 litres of clean water. Using ten levels of these concentrations, five sandcrete blocks of size 150mm cube were produced for each concentration, making a total of fifty blocks and the compressive strengths at 28 days were determined. Using a concentration of 50g/l, twenty blocks were produced with 0, 5, 10, 15, 20, 25, 30, 35 and 40% respectively by weight of cement reduced making a total of 180 blocks. They were subjected to compressive strength test on 7, 14, 21 and 28 days respectively, crushing five blocks in each day to determine their average compressive strength. In order to investigate the effect of duration of soaking the locust bean pod cover in water on the compressive strength of the sandcrete blocks, five blocks were produced using the same concentration of 50g/l but soaked in water for 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 days respectively and their compressive strengths were determined at 28 days. It was found that the higher the concentration of the LBPS, the more the compressive strength and soaking the locust bean pod cover for more than 24 hours is not necessary as the compressive strength tends to decrease. In conclusion, up to 25% by weight of cement can be saved by using locust bean pod solution in moulding the sandcrete blocks. Keywords: Cement, compressive strength, locust bean, sandcrete blocks, building

Optimizing Properties of Sandcrete Blocks Produced In the Warm-Humid Climatic Zone Of Nigeria

In the Nigeria construction industry, non compliance to existing standards has been one of the major causes of substandard material production and to an extent poor housing development. It has therefore degenerated to the inability of dictating standards with the performances of building materials in the industry. The threat of this ugly situation grows higher when materials of composite natures are involved. In this era of innovation in the construction technology generally, the study focuses on providing a more reliable and faster mean to producing sancrete blocks of desired properties starting with Warm Humid Climatic (WHC) zone of Nigeria. In the beginning, field survey method was adopted to obtain information on the apriori knowledge of the common nominal mix ratio used in producing sandcrete blocks in the area. The information was used as a basis for designing the sandcrete mixes using Box-Wilson symmetric Composite Plan Bm. Laboratory experimental tests were carried out on the blocks produced with the various mix designs to obtain values on their density and compressive strength properties. Polynomial regression models were therefore developed, and subsequently tested to certify their fitness considering only the independent variables (cement, water, and sand aggregates) that are significant for the respective properties. Mono-factorial effects of the variables were investigated on the properties to ascertain the degree of their influences on the respective properties. Progressively, optimal equations of the final regression models were therefore developed having optimized the respective significant variables in the models, using the quadratic equation for blocks of optimum and desired performances. To this end, nomograms were therefore constructed with the optimal values derived from the optimal equations to reflect various optimum compositions of the constituent ingredients (variables) for certain desired properties of the blocks, depending on the functional requirements or purposes of use. In the light of this rare development, speedy decisions productions of the blocks of desired properties will be possible and accurate. Production of the targeted properties of the blocks would therefore, not be hindered by the limited quantity of any of the ingredients, since there are possibilities of other optimum compositions that would accommodate the limitation in quantity of the said ingredient.

COMPARATIVE ANALYSIS OF THE COMPRESSIVE STRENGTH OF HOLLOW SANDCRETE BLOCKS WITH DIFFERENT CAVITIES ARRANGEMENT

Previous analysis showed that cavity size and number on one hand and combinations thickness affect the compressive strength of hollow sandcrete blocks . Series arrangement of the cavities is common but parallel arrangement has been recommended. This research performed a comparative analysis of the compressive strength of cavities of different configurations. The test thin plate distributes the load on the block and the hollow block is regarded as a two way slab. The results showed that at equal end-web to centre -web thickness (1:2) and total cavity volume the stresses in the parallel configuration were higher than those in series configuration. The minimum stresses in the series arrangement were lower than the corresponding values in the parallel arrangement. In addition, the maximum stresses in the series arrangement were lower than the corresponding values for parallel arrangement. The implication is that at same volume and number of cavities and web thickness, the series arrangement results induced least stress. http://dx.doi.org/10.4314/njt.v35i2.3

THEORETICAL INVESTIGATION OF STRESSES DISTRIBUTIONS IN HOLLOW SANDCRETE BLOCKS DUE TO VARIATION OF CAVITY SIZES AND NUMBER WEB THICKNESS

The relationship between cavity size and number on one hand and combinations of web thicknesses were investigated theoretically. The least number of cavities was 4 for end-web to centre web ratio of 1:2 at constant shell thickness with the least web thickness equal to 12.5mm. The effects of the number of cavities and web thickness on strength were also investigated. The test thin plate distributes the load on the block and the hollow block is regarded as a two way slab. One of the principal findings is that the variation of maximum stresses with the number of cavity is Gaussian for end-web to centre-web ratio of 1:1 but polynomial for 1:2. In addition, the lowest stress is induced when the end to centre ratio is one. The maximum stress, (21.5N/mm 2 ) occurred at the cavity length (a * ) of 125mm for 3 cavities while the end (end centre) web thickness (t) was 25mm respectively. In order words, this combination should be avoided as it will lead to creation of highest stress in the hollow sandcrete blocks. The configuration which will result in least stress (0.5N/mm 2 ) is ( a * , N, t) = (50mm, 4mm, 50mm). However, this combination also gave a high maximum stress (6.9N/mm 2 ) in a web, implying that the right choice of configuration should be rather the one that creates the smallest set of maximum stresses in all members. Overall, the best configuration is 2 cavities with web thickness 50mm for an end web to centre web ratio of 1:1 (3.3N/mm 2 ). The corresponding values for 1: 2 ratios are 3 cavities with 50mm shell thickness (4.8N/mm 2 ). The method presented showed meaningful insight could be investigating theoretically. http://dx.doi.org/10.4314/njt.v35i2.4

COMPARATIVE STUDY OF INTERLOCKING AND SANDCRETE BLOCKS FOR BUILDING WALLING SYSTEMS

The high cost of building materials, especially sandcrete blocks in Ghana, has made building construction products expensive and created a housing deficit of about 1.6 million. Meanwhile, the interlocking blocks, which are made up of laterite and cement abound could be exploited to help reduce the cost of housing construction. Especially, wall construction which is one of the major components of the entire building process. This paper sought to explore the possibility of adopting the interlocking block wall system as a means of making wall construction of buildings affordable in Ghana. A comparative study using interlocking blocks system and sandcrete blocks was made. An observation of the processes were made to identify the extent to which each system falls in line. A sample size of 45 respondents comprising 20 workers of P-A Capital Estate Housing, 5 personnel from consultancy firms and 20 private individuals were selected for further confirmatory study with the use of convenience and purposive sampling technique. To determine whether there were any statistically significant differences between the mean values, paired-sample t-test at the 0.05 level of significance was done. Results showed that, the use of interlocking blocks do not only lead to elimination of a number of non-value adding activities associated with the use of the sandcrete blocks, but also make the wall construction process cheaper and faster. It was also discovered that the absence of mortar jointing in the interlocking system reduced the quantity of materials, like cement and sand, required in the sandcrete wall construction process. Furthermore, there was no statistically difference between the compressive strength of interlocking blocks and conventional sandcrete blocks. However, there were statistically significant differences between construction cost and speed of construction using the two systems of construction.

Exploring the Potential of Alternative Pozzolona Cement for the Northern Savannah Ecological Zone in Ghana

This project evaluates the performance of pozzolana cement elements produced from alternative raw materials with a view using them in low-cost housing. It also seeks the reduction of waste from agricultural sources and the cost of sandcrete blocks by using locally available materials. The need to find alternative materials to replace existing conventional ones has necessitated research into substitutes to cement with a view to investigating their usefulness to wholly or partly substitute ordinary Portland cement in the production of sandcrete blocks. This project investigates the possible use of Corn Cob Ash (CCA) as a partial replacement of cement in sandcrete block production. 140 no. 450mmx150mm×225mm solid sandcrete blocks of mix ratio 1:8 were cast, cured and crushed at 7, 14, 21, and 28 days. The corn cob ash was replaced at 0 to 40 percent levels at 5% intervals. The maximum compressive strength of 2.10 N/mm2 was recorded at 30% replacement on the 28th day. After 12 months of exposure under northern savannah climatic conditions, the compressive strength remained stable or even increased with the weathering exposure. The maximum value of 2.10N/mm2 for the 30% replacement level is found suitable and recommended for building construction having attained a 28-day compressive strength of more than 2.0N/mm2 as required by the National Building Code for non load bearing walls.

EFFECTS OF POLYTHENE FIBRES ON SELECTED PROPERTIES OF SANDCRETE BLOCKS

The aim of this study is to explore the possibility of using polythene fibres to increase the strength of sandcrete blocks without increasing the weight and cost of production. It is a comparative study of the properties and performance of polythene reinforced and plain sandcrete blocks. The graded soil sample has a specific gravity of 2.64. Polythene fibres were got from shredded sachet water bags. The fibres were mixed at 0.25%, 0.50% and 0.75% by mass of the block with sand and cement to produce the reinforced sandcrete at water – cement ratio of 0.4. Compressive strength, water absorption, split tensile strength tests were carried out on the various samples. The results show that the addition of polythene fibre to sandcrete blocks has very little effect on the compressive strength, although at 0.5% fibre content, the tensile strength increased. Heating the blocks at 100 o C for 24 hours, the compressive strength of the heated blocks are higher than the non - heated blocks. The results reveal that at an optimum fibre content of 0.5%, fibres are good in reinforcing sandcrete blocks if heated. Addition of polythene fibres to sandcrete blocks will increase the tensile strength and can limit the propagation of cracks. http://dx.doi.org/10.4314/njt.v35i1.6