Recycling fine sandcrete block waste (FSBW)as fine Aggregate in the production of sandcrete Block

The study investigated the use of Fine Sandcrete Block Waste (FSBW) as fine aggregate in the production of sandcrete blocks with a view of controlling waste and decongesting block molding production sites. Standard sandcrete blocks of size 450mmX225mmX225mm were prepared from a mix ratio 1:6 (cement: fine aggregate) containing sand and FSBW as fine aggregates. The sand was partially replaced by FSBW in the mix within the range 0% - 90% in steps of 10%. The blocks were cured for 28 days and then tested for compressive strength. The physical properties of both the sand and FSBW were also determined. The results of the study revealed that the physical properties of FSBW compares favorably with those of conventional sand with the exception of water absorption. It further showed that the density and the compressive strength of the tested blocks decrease as the percentage replacement of sand with FSBW increases. The density of the blocks varied linearly with the compressive strength. Blocks prepared for mixes having 50% FSBW content or less were found to satisfy the minimum recommended compressive strength of 3.45N/mm2 (NIS 87:2000)

Properties of Concrete Incorporating Calcinet Earthworm Cast as Partial Replacement for Cement

The high cost of cement is a major drawback in concrete usage. This research aimed at determining the strength charac t eristics of concrete incorporating calcined earthworm cast as partial replac e ment of cement . The objectives were to obtain the optimum percentage of calcined earthworm cast that can be used to replace cement in a given concrete mix , and to ex amine the physical I chemical properties of the calcined earthworm cast. Percentage replacement of cement with the earthworm cast was done at 0, 10 , 20, 30% respectively and tests were carried out on fresh and hardened concrete. The results showed that while the initial and final setting time of the concrete containing earthworm cast increased with the increase in earthworm cast content, the compressive strength decreased with increase in ca lcin ed ea rthworm cast replacement . It was concluded that a partial replacement of not more than 30% of cement with calcined earthworm cas t will suffice

In-situ Behaviour of Selected Local Sand Binders on Microstructure and Mechanical Properties of Grey Cast Iron

The need to develop local sand binder by manufacturing industries has become necessary for national development. In this paper, the suitability of selected local sand binders on microstructural and mechanical properties of sand cast-grey cast iron was examined. The bentonite, cassava starch, rubber latex is varied for 5w% - 11w% fritter added to 100% silica sand of 5w% water. The selected scrap was superheated to 1550oC with 0.1% (Fe-Si) inoculant for proper dissolution. The microhardness and tensile properties were examined using Brinnel hardness (HBN) and Instron Tensiometer (1195) for tensile values (MPa) respectively. The microstructural properties of the produced cast were examined through Nikon metallurgical microscope. Results obtained from the grey cast revealed a pearlite matrix interface, massive carbide and graphite phases. Molds bonded with bentonite and cassava starch appears better with average hardness value of 437 and 385 (HBN) respectively. The microstructure was seen to be dominated by majorly pearlite matrix with little carbide which are favorable for the formation of gray cast iron which requires low chilling in the moul

A Comparative Analysis of Batching by Weight and Volume towards Improved Concrete Production

Batching of concrete is generally the proportioning of the different constituents of concrete before mixing which could be by weight or volume. Mix-design justified by trial test is the best method to achieve a concrete of desired properties. Standardized prescribed concrete (SPC) mix-design is mostly adopted in mass concreting to high strength concreting applications in most developing nations. British standards accept volume batching for SPC only in mass concrete (<15 MPa) but batching by weight for normal and higher strength concrete. Structural concrete like in storey buildings requires at least a normal strength concrete (>20 MPa) recommended to be batched by weight. Designs batched by volume have been identified as the most commonly used method in concrete production in Nigeria and most developing nations, especially by medium to small scale construction firms due to the very high cost of employing batching plants. This research work developed a modified volumetric batch mix-design that will be equivalent to SPC design mix batched by weight in normal and higher strength concrete. The physical properties of the constituent concrete materials, fine aggregate, 12 and 19 mm sized coarse aggregates were determined. The strength of SPC mix of ST2, ST4, and ST5 to British standard were determined when batched by weight and their volume equivalents mix-design batch determined. The strengths of these SPC mixes were batched by volume and their weight equivalent batch-design determined. A relationship was determined between both batching mixdesign methods for all the prescribed mixes and strengths using the binder-aggregate and coarsefine aggregate ratios, such that the preferred weight batching design mix could be achieved by a modified mix-design batched by volume. This study concludes that concrete mix-design batched by weight is superior to when batched by volume and the desired design batching by weight could be achieved by generating a modified mix-design-batch by volume. This will improve the quality of concrete storey buildings in most developing nations

EFFECTS OF PARTIAL REPLACEMENT OF SAND WITH LATERITIC SOIL IN SANDCRETE BLOCKS

Of recent, the attention of most researchers is shifting towards the optimization of building materials by using local contents; the use of indigenous materials; and local industrial by-products unique and abundant in certain localities. This study therefore explored ways in which lateritic soil could be utilised in hollow sandcrete block production in Ota, Ogun State, Nigeria. Sandcrete blocks were made with lateritic soil taken from different sources replacing the conventional fine aggregate (local river sand) in steps of 10% up to 60%. Their compressive strengths determined to check for conformity with standard sandcrete block as specified in the Nigerian National Building Code (2006) with a view to determine the acceptable percentage replacement. Soil tests were performed on the lateritic soil samples to characterise the soils. Classification of the lateritic soil samples within Ota, revealed that the lateritic soils are mostly sandy clay of high plasticity and may replace sand by up to 20%, though an approximate linear decrease in strength with increasing sand replacement with lateritic soil was observed. This percentage replacement can be recommended to the block making industries within Ota with a view to encouraging utilization, though it is encouraged to confirm the percentage before embarking on mass block production

Prefabrication Method of Building Construction in Lagos State, Nigeria: Prospects and Challenges

Though the use of prefabricated elements in construction has been considered as one of the most effective methods, the industry has found difficulties implementing it. The paper provided an overview of the challenges and factors influencing the use of prefabrication in Lagos state. A survey technique was adopted in carrying out this research. This paper studied 100 prefabricated home owners and occupants, and 25 professionals with knowledge and skill in the construction of prefabricated buildings in Lagos state. Two different questionnaires were administered, one to prefab building occupants/clients and the other was administered to professionals in the prefab industry survey based on 5-likert scale. Statistical package for social sciences (SPSS) was used to process and analyze the data obtained from the questionnaires. The use of prefabricated elements in building construction is observed to be an effective and efficient approach to improving construction processes and productivity, ensuring construction quality and reducing time and cost in the construction industry. However, many problems occur with this approach in practice, including initial high cost of construction, unawareness of the prefabricated method of construction, unavailability of prefabrication companies locally, technically and challenges in installation. The study concluded that though there are lots of factors influencing the use of this method of construction, the benefits should be put into effective use. The use of prefabricated elements in building construction in Lagos state is profitable due to the benefit of faster construction time because of the nature of the city and the increasing population of the city. Recommendations were provided to further the use of the prefabricated method of construction more effectively

Data on mixing and curing methods effects on the compressive strength of concrete

Curing, though important is sometimes underrated in concrete production. This dataset provided shows the effects of four (4) different methods of curing on two distinct mix ratios. The data provided in this article are for a study that was conducted on one hundred and sixty (160) cube samples of mix ratios 1:2:4 and 1:1.5:3 while employing four (4) different methods of curing. The data given in the article displays the finding of the study. The findings can aid in prediction and optimization of concrete behavior and compressive strength when any of the curing methods are utilized

COMPARATIVE ANALYSIS OF CONCRETE STRENGTH UTILIZING QUARRY-CRUSHED AND LOCALLY SOURCED COARSE AGGREGATES

The use of two types of course aggregates for different works is examined in this study. Typical strength concrete is being made from various aggregates and their impact on various characteristics to the subsequent concrete. Compressive strength is the most vital property of a concrete. In this paper, two forms of coarse aggregates, crushed stone(granite) and unwashed gravel were utilized. Sharp sand is the fine aggregate. Initial laboratory examination was carried out to establish the appropriateness of utilizing the aggregates for construction purpose. Particle size distribution (sieve analysis) and slump test were investigated. Mix ratio (1:2:4) was used for this work and mix structures were analyzed by absolute weight technique. A total of 32 cubes (150×150×150mm) were cast to permit the compressive strength to be observed at 7, 14, 21 and 28 days. Test results revealed that concrete produced from unwashed gravel has a better workability than crushed granite. Higher compressive strength at all period was observed with concrete produced from granite aggregate. Compressive strength patterns were suggested as a result of age at curing