scholarly journals Estimating the original cement content and water–cement ratio of Portland cement concrete and mortar using backscattered electron microscopy

2013 ◽  
Vol 65 (11) ◽  
pp. 693-706 ◽  
Author(s):  
Hong Seong Wong ◽  
Kyle Matter ◽  
Nicholas R. Buenfeld
1976 ◽  
Vol 3 (1) ◽  
pp. 68-82 ◽  
Author(s):  
Ram S. Ghosh

A method is described for proportioning fly ash concretes to produce similar compressive strengths as normal Portland cement concrete at 3, 7, 28, and 90 days. The method is primarily based on the Abrams' law relating compressive strength and water–cement ratio. Curves are also presented, for estimating the most economical fly ash to cement ratio for a particular strength and cost of fly ash.


2015 ◽  
Vol 77 (32) ◽  
Author(s):  
David Yeoh ◽  
Koh Heng Boon ◽  
Norwati Jamaluddin

This research is an exploratory experiment into sulfur concrete used not as a complete replacement of cement but as an additional material in percentage of the cement content. The aim of this research was to explore the possible appreciation of mechanical and physical properties of concrete containing sulfur with percentages of 1%, 5% and 10% of the cement content. The sulfur used here was not heat-activated, hence the binding effect in sulfur was absent. The experimental results revealed that concrete containing sulfur did not perform better in their strength properties, both compressive strength and flexural strength. The physical properties such as water penetration and water absorption for concrete containing sulfur also showed poor performance in comparison to ordinary Portland cement concrete. Such phenomena are very likely due to the sulfur not being activated by heat. Carbonation test did not show good results as a longer term of testing is required. Drying shrinkage property was found to be encouraging in that concrete containing 10% sulfur had quite significant reduction in drying shrinkage as opposed to ordinary Portland cement concrete. 


2018 ◽  
Vol 7 (4.37) ◽  
pp. 138
Author(s):  
Asst. Prof. Dr. Khawla H. H. Shubber ◽  
Eng. Sajjad Hashim Mohamed

This research represents a trial of understanding and improving mechanical properties of base or subbase granular materials, used in pavement construction, stabilized with Portland cement known as cement treated base (CTB) in terms of density, optimum water content (O.W.C), and compression Strength of three curing ages (3, 7, 28) days under different situations. Different Portland cement percent of (0, 5, 7, 10, 12, and 15) % by weight were added to selected base course granular materials (type B according to local standard specification in Iraq). Results showed that the density of mixture increase with increasing added cement percent, while O.W.C takes its maximum value around 7% cement content, and compression strength increase with increasing cement content and curing age. Then effect of replacing 50% of natural granular materials by waste Portland cement concrete (WPCC) was investigated on the results of (0, 7& 15)% cement content on density, O.W.C and compression strength in the three curing ages. Results reveled although density of mixture cooperating WPCC for 0% cement content was higher, CTB of natural granular material were denser. On the other hand compressive strength decrease in case of using WPCC for all percent cement added and curing ages. Finally, effect of soaking in water on CTB with (7 &15)% cement compressive strength of three curing ages was studied, under three period of soaking (1 week, 2 weeks, &one month). Test results exposed that, CTB Compressive strength increase with increasing soaking period but still less than that of un-soaked and for all curing ages. For each test stage mathematics relationships with acceptable correlation were presented proofing test results tendency.  


2011 ◽  
Vol 179-180 ◽  
pp. 978-982
Author(s):  
Xiao Yong Li ◽  
Zhi Gang Zhang

Slurry trench cutoff walls, constructed using self-hardening cement-bentonite (SCB) are the most common form of in-ground vertical contaminant barrier in the world, and are increasingly being used in China. As a kind of vertical anti-seepage wall material, SCB slurry is requently used for the containment of contaminated groundwater and other envirofunental Protection Projeets abroad. Domestie applieation of cement-bentonite slurry walls is not extensive. The objective of this study was to evaluate the effect of water-cement ratio and cement content on the hydraulic behavior of SCB and soil–bentonite (SB) mixtures permeated with water. The experimental program included unconfined compression tests, expansion ratio tests and hydraulic conductivity tests. The test results indicated changes in hydraulic conductivity take place due to the variation of the water-cement ratio and permeant fluid. Cement is a main material in effecting the CSB strength of unconfined compression. Cement greatly influenced the CSB permeability coefficient. Addition of Portland cement to the SB mixtures increased their hydraulic conductivity when permeated with water. The hydraulic conductivity of the SCB specimens permeated with water was inversely related to the cement content.


2011 ◽  
Vol 194-196 ◽  
pp. 1049-1052
Author(s):  
Jun Wang ◽  
Zi Jian Zhang

The water-cement ratio and cement content are key factors which reflect the anti-penetration of the concrete. To study the slag cement concrete against sulfate attack, make two types of the slag cement concrete test blocks of which one type has the same concrete content and different water-cement ratio, while the other type has the same water-cement ratio and different concrete contents; then test the concrete test blocks on compressive strength, folding strength and weight changing after dipping them into sulfate solution and drying them for thirty and sixty times .At the same time non-damage ultrasonic test was carried out. The results show the durability of the slag cement concrete is improved with the decrease of water-cement ratio; in concrete design, there is optimum cement content which theslagcement concrete has the best resistance sulfate erosion.


1997 ◽  
Vol 503 ◽  
Author(s):  
B. K. Diefenderfer ◽  
I. L. Al-Qadi ◽  
J. J. Yoho ◽  
S. M. Riad ◽  
A. Loulizi

ABSTRACTPortland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. By developing techniques that would enable civil engineers to evaluate PCC structures and detect deterioration at early stages (without causing further damage), optimization of life-cycle costs of the constructed facility and minimization of disturbance to the facility users can be achieved.Nondestructive evaluation (NDE) methods are potentially one of the most useful techniques ever developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part, termed the “loss factor,” describes the conductivity of PCC and the attenuation of electromagnetic waves.Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1 to 40.1MIHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation. A new capacitor probe has been developed which consists of two plates, located within the same horizontal plane, for placement upon the specimen to be tested. Preliminary results show that this technique is feasible and results are promising; further testing and evaluation is currently underway.


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