INVESTIGATING THE PROPERTIES OF CONCRETE INCORPORATING CALCINED EARTHWORM CAST AS PARTIAL REPLACEMENT FOR CEMENT.

ABSTRACT Concrete is a major material in the construction industry in Nigeria and the world at large, either mass concrete alone or sometimes complimented with other materials like steel. Calcined earthworm cast is cast that has been subjected to great heat. The primary aim of this research was to determine the strength characteristics of concrete incorporating calcined earthworm cast as partial replacement of cement. The objectives were to to obtain the optimum percentage of calcined earthworm cast that can be used to replace cement in a given concrete mix, and to examine the physical and chemical properties of the admixture (calcined earthworm cast). From the tests carried out on the characteristic of concrete using earthworm cast as a pozzolana, it was concluded that; the initial and final setting time of the concrete containing earthworm cast increases with the increase in earthworm cast content. The specific gravity of calcined earthworm cast is 2.38. The bulk density of calcined earthworm cast is 1294 kg/m3. In all mixes, compressive strength decreased with increase in calcined earthworm cast replacement. The compressive strength of concrete obtained ranged from 25.16 to 15.66 N/mm2 with 0, 10, 20, 30% replacement earthworm cast replacement of cement achieved above 70% of the required strength of the concrete while the 40 % replacement failed to reach 70% of the expected strength

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

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)

The Influence of Training on Bricklayers’ Productivity in Nigeria

The global economic situation and the need for construction contractors to remain in business in this competitive environment have made productivity improvement more and more important. This study therefore investigated the impact of formal and informal trainings on the productivity of bricklayers in three commercial nerve centres of Nigeria (Lagos, Abuja and Port Harcourt).To achieve this, questionnaires, backed up with interviews and on-site measurements were conducted on the management and bricklayers of construction firms who were randomly drawn from the three categories of construction firms in the country (large-sized, medium-sized and small-sized firms). 90 and 180 structured questionnaires were distributed to the management and bricklayers in the study area while 72 and 118 questionnaires were respectively filled and returned in this regard. The results of the descriptive and inferential statistical techniques indicated that training had significant effect on the productivity of bricklayers in Nigeria. Other factors such as monetary and nonmonetary incentives, planning and control, organizational strategy, supervision aspects and general management also had their contributory effects to bricklayers’ productivity. The study concluded that the issue of training should be accorded a priority attention by the managements of construction firms in order to attain greater workers’ productivity on construction sites

BUILDING INFORMATICS NEURAL NETWORK AND REGRESSION HEURISTICS PROTOCOL FOR MAKING DECISIONS IN BUILDING CONSTRUCTION PROJECTS

Building Informatics is a body of knowledge that uses the ICT computer system, digital systems, building information modeling, and state-of-the-art software in solving technical and management issues in building and construction fields. One of the modern methods used in data forecasting and modeling is Artificial Neural Networks, considering its advantage over traditional regression method. A data sample was taken of 1500 residential building projects’ completion costs. Regression analysis was carried out and model validated with functionality and Jackknife re-sampling technique. 150 Questionnaires were used to capture data on factors influencing application of heuristics protocol for decisions in residential building construction projects and data samples were analyzed using severity index, ranking, and simple percentages. Analysis of data brought up some factors that influence effective application of heuristic protocol in solving decision problems in construction decision process. The linearity analysis was carried out on the model and results indicated high level of tolerance and -0.0876 lowest variation prediction quotients to 0.9878 highest variation quotients. Also, 0.069 regression model fitness coefficient (R-square) was generated with 0.9878 highest variation quotients with standard error of 0.045. The results data attests to the stability of the model generated and the model is flexible in accommodating new data and variables, thus, allows for continuous updating

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

An Empirical Investigation on the Benefits and Leakages in the Use of Web-Based Technologies in the Construction Industry

The internet and the World Wide Web (WWW) has the capacity to link the construction industry and its stakeholders to the desired smart and seamless future, although there are several leakages that have engendered the slow and low adoption in the construction process. Therefore, the study examined the benefits and leakages in the use of web-based technologies in the construction industry. The research selected registered construction professionals through a simple random sampling method from Lagos and Abuja (FCT). A total of 1,160 construction professionals participated in the study. A structured questionnaire was used as the principal instrument for obtaining primary data in form of responses from the construction professionals. Using a system block diagram, the study designed a web-based system using MySQL connected to the HTML web-interface through a PHP script processing the data back and forth. The study revealed that the use of web-based technologies in the construction industry can be engender efficient recording benefits, optimized production benefits and effective information processing. However, there are leakages such as usage risk leakages, culture leakages and tools leakages that may hinder the integration of web-based technologies in the construction processes. The study developed a framework for a web-based material planning and control system that can be used in the building materials’ planning and control processes that ensures that building materials information are archived, stock levels are identified and material delay is minimized. The study recommended the use of web-based technologies in several of the construction processes by harnessing its benefits. Efforts should be made to increase ICT training and education amongst construction professionals to intensify the proficiency of stakeholders in the use of web-based technologies in the construction industr

COMPETITIVE STRATEGIES OF INDIGENOUS CONSTRUCTION FIRMS

The Nigerian construction market is one of the most vibrant and largest in Africa. However, indigenous construction firms (ICFs) in Nigeria struggle to survive in a harsh business environment characterized by intense competition and relatively low profit margin. Hence, the aim of this study was to explore the competitive strategies adopted by ICFs in order to improve their competitiveness in spite of stiff competition. The study adopted a cross sectional survey research approach with the use of questionnaires. Seventy two (72) well-structured copies of the questionnaire were distributed to ICFs in Lagos and Abuja, Nigeria based on convenient sampling technique. Data obtained was analyzed by means of descriptive statistics and Spear man’s rank correlation. The findings of the study showed quality in constructed facilities as the most significant competitive strategy of ICFs. The study also indicated a strong and positive correlation between the competitive strategies of quality, schedule and cost. Since tradeoffs in any of these three (quality, schedule and cost) basic project performance criteria can have a devastating impact on project performance, the study concludes that ICFs adopt innovative and inclusive competitive strategies that focus on quality while attempting to achieve on-schedule performance and cost reduction in construction operations

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