Extending the life of concrete-mixer components

2012 ◽  
Vol 32 (3) ◽  
pp. 229-236
Author(s):  
G. I. Bondareva
Keyword(s):  
Wear ◽  
2021 ◽  
pp. 203830
Author(s):  
W.S. Labiapari ◽  
R.J. Gonçalves ◽  
C.M. de Alcântara ◽  
V. Pagani ◽  
J.C. Di Cunto ◽  
...  

Author(s):  
Saji K. G. ◽  
Zubair M. ◽  
Sreelatha B. Nair ◽  
Varghese P. R.

Background: Construction industry chiefly depends on the cement. The constituents in the cement have various health effects in the exposed group. The present study focused to realize the health effects of cement exposure and duration of exposure.Methods: The sample size was 831 male workers. The labourers included were construction workers (masons, helpers and concrete mixers) and cement loading and unloading workers. They were categorized in to five groups which were 5-9, 10-14, 15-19, 20-24 and 25+ years based on the duration of exposure to cement. Health hazards among these labourers were categorized in to lung function impairment symptoms, cutaneous symptoms and other symptoms.Results: High frequency of respiratory tract ailments (persistent cough 54%, breathlessness 47%) was observed among loading workers as they were handling cement dust. Burning was the most observed one in concrete mixer (70%), hair loss and change in hair colour was observed in 60% of all categories of workers. Skin related ailments were more prevalent among masons, helpers and concrete mixers.Conclusions: The frequency symptoms had correlation with their nature of work in the construction industry. Prolonged exposure to hazardous substances will decline the efficiency of labourers by malfunctioning their physiological functions. Proper awareness about the hazardous substances and well taken precautions among these labours can enhance their efficacy and wellbeing. 


Author(s):  
Hossam S. Badawi ◽  
Sherif A. Mourad ◽  
Sayed M. Metwalli

Abstract For a Computer Aided Design of a concrete truck mixer, a six cubic meter concrete mixer drum is analyzed using the finite element method. The complex mixer drum structure is subjected to pressure loading resulting from the plain concrete inside the drum, in addition to its own weight. The effect of deceleration of the vehicle and the rotational motion of the drum on the reactions and stresses are also considered. Equivalent static loads are used to represent the dynamic loading effects. Three-dimensional shell elements are used to model the drum, and frame elements are used to represent a ring stiffener around the shell. Membrane forces and bending stresses are obtained for different loading conditions. Results are also compared with approximate analysis. The CAD procedure directly used the available drafting and the results were used effectively in the design of the concrete mixer drum.


2019 ◽  
Vol 292 ◽  
pp. 9-14 ◽  
Author(s):  
Oldrich Sucharda ◽  
Vlastimil Bilek

Concrete is typical composite material and its properties can be very variable. Material properties are also influenced with the technology of processing, manufacturing and treatment after concreting. Reinforcement in form of fibers is often added for improving tensile strength. This paper deals with specific testing of fibre concrete. Test results of series of specimens are presented for selected transport concrete composition, which is reinforced with amount of fibers 25, 50, 75 kg / m3. Fibers were added directly into the into the concrete mixer in the factory. Each series includes more than 25 test samples. The tests include the compressive strength of a cube and cylindrical, testing of modulus of elasticity, and the split tensile strength in the direction perpendicular to and parallel to the filling. Within the research project also a few types of bending tests were performed. Four variants of bending test that vary in span of 500 or 600 mm, samples with and without a notch, and in a three- / four-point configuration. As a summary, broader evaluation and functional dependencies are derived.


Author(s):  
Md. Shahiduzzaman ◽  
E. Owen

Calcium hydroxide (Ca(OH)2) is widely available in Third World countries because of extensive limestone deposits. Previous studies (reviewed by Owen et al 1984) have shown Ca(OH)2-treated straw to be prone to mouldiness and low intakes. Urea was added to Ca(OH)2 in the present study to inhibit mould and supply nitrogen. Two experiments are reported which investigated the amounts of Ca(OH)2 and urea required for improving intake and digestibility of barley straw in sheep.Forty Suffolk x Mule store lambs (20 castrates, 20 ewe lambs) aged 8 months were used to measure intake and digestibility of 5 straws (Table 1) in a randomized block experiment, with blocking according to weight and sex. Animals were fed restricted concentrates (Table 1) and ad libitum straw (allowing refusals of 25% of intake) over a period of 35 days, with collection of faeces over the last 8 days. For treatment, straw was chopped, mixed with chemical solutions (Table 1) in a concrete mixer, and “ensiled” for 60 days (September & October) at 500 g dry matter (DM) per kg, in plastic bags contained in 45-gallon oil drums. Straw was aerated for 3 days before feeding. Untreated straw was simply chopped before feeding.


2020 ◽  
Author(s):  
Yifeng Jiang ◽  
Gangfeng Tan ◽  
Haoyu Wang ◽  
Zelong Wang ◽  
Zhenyu Wang ◽  
...  
Keyword(s):  

2016 ◽  
Vol 249 ◽  
pp. 73-78 ◽  
Author(s):  
Vladimír Suchánek ◽  
Kateřina Hájková

This report deals with long term monitoring of durability properties of concrete using different weight doses of various kinds of additions. Particularly limestone, silica fume as a 50% suspension and blast furnace slag were used. Even though the basic recipe is based on the designed concrete, all the fresh concrete was made with a free-fall concrete mixer in the laboratory. This report deals with long-term monitoring of cement concrete surface resistance to water and defrosting chemicals (achieved 475 cycles). The article also describes results of following tests: determination of concrete frost resistance, depth of water penetration under pressure and depth of chloride penetration. Standard tests of fresh and hardened concrete specimens complement the experiment.


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