Load - Deflection Characteristics of Reinforced Concrete and Reinforced Latecrete Beams at Mid-Span

A laboratory Investigation of the Flexural Strength of Latecrete materials was carried out. The laterite used falls under AASHTO soil classification A-7-6 (10) with low plasticity clay (CL) according to the Unified soil classification system. This laterite is within zone four gradation characterized by fine laterite and has kaolinite as its dominant clay mineral. The Experimental programme involves the fabrication of twenty beams of concrete and latecrete materials; and testing them for flexural strength. Tests show that The Flexural strength recorded for plain concrete beams was 2.89 N/mm2, while plain latecrete beams has a value 1.44 N/mm2. The flexural strength of 13.58 N/mm2 was recorded for the reinforced concrete beams and 7.80 N/mm2 for reinforced latecrete beams, indicating that the flexural strength of latecrete beam is approximately 50% of that of concrete beam specimens. The load-deflection behaviors of the beams are essentially linear within the elastic range of loading. Based on the findings of this investigation, it was observed that the behavior of latecrete is similar to that of concrete; however, the concrete materials showed better strength characteristics than the latecrete materials. Keywords: Concrete, Latecrete, sand, Reinforcement and flexural strength

Performance of lateritic concrete under environmental harsh condition

This is an investigation of weathering characteristics of Laterized concrete with laterite-fine aggregate ratio as a factor. It was done with a view of ascertaining the suitability of laterite as aggregate substitutes at 0, 10, 20, 30 and 40% of fine aggregate used in the construction industry. The weathering characteristics were examined by conditioning laterized concrete cubes to varying temperatures, chemical and alternate wetting and drying, which all represent the operating weather conditions (wet and dry seasons) in tropics, including Nigeria. The mix proportion used was 1: 2: 4, the curing age of the laterized concrete was based on 28days curing age, while the compressive strength of the treated laterized concrete cubes was determined. The result of this research showed that the compressive strength of laterized concrete with laterite-fine aggregate ratio variation decreases when subjected to alternate wetting and drying and increases when subjected to magnesium sulphate (Mg2SO4). It was also discovered that a laterized concrete with a laterite-fine aggregate ratio of 20% conditioned to a temperature range of 100oC attained optimum compressive strength of 12.90 Nmm-

Security Algorithm for Preventing Malicious Attacks in Software Defined Network (SDN)

This paper explores the success record of the Internet as well as its shortcoming in the area of network configuration, response to fault(s), load and change(s) that led to the concept of Software Defined Network (SDN).These are the factors that separated combined net­work’s control from forwarding planes for easier optimization, programming of network and centralization of control logic capabilities. These had also led to new different challenges, that open doors for new threats that were not existing or harder to exploit. SDN prototype embraces third-party improvementas a result of hard work, that later makes the SDN vulnerable to potential trust issue on its applications (apps).This makes it possible for an intruder toinsert malicious content/programs into the network packets and then forward into the network.Codes were written to implement the designed algorithm using white/blacklist source identification combined with Hash Bayes' Theorem (W/B+HBT) content filter as a security measure to prevent the malicious attack(s). It was shown that new transaction(s) from known attack source(s) are classified as Blacklist and dropped, while those known as whitelist are forwarded to their respective destination as a legitimate packet(s) (W/B). Those from unknown sources were treated using Hash Bayes’ Theorem (HBT) content filter. The result of the implementation is able to record 10% false positive (FP) and false negative (FN) and 90% true positive (TP) and true negative (TN) (accurate classification of packets) for the presented algorithm

Effect of heat on laterised concrete

This study presents the results of investigation of the effects of temperature variation on the compressive strength of laterised concrete. Cube specimens were cast, cured in water at ambient laboratory temperature and subjected to different temperature regimes before testing. A concrete mix ratio of 2:3:6 (cement: laterite/sand: granite) with water/cement ratio of 0.65 was adopted for this investigation. The laterite content in the fine aggregate was varied from 0 to 100% at 25% interval. Specimens cured for 7 and 28 days were subjected to uniaxial compressive loading tests at room and elevated temperatures of 250, 500 and 750oC. The results show that normal concrete cannot withstand appreciable load above 250oC while laterised concrete with 25% laterite in the fine aggregate is able to resist higher load with increase in age and at temperature up to 500oC. It is also observed that there is no appreciable increase in strength at higher temperatures. The peak compressive strength value of 30.44 N/mm2 is recorded for the mix with 25% laterite-75% sand at 500oC. This is an indication that the strength of laterised concrete is generally sufficient for use at elevated temperature not exceeding 500oC