Study the retardant effect of using different sugar's types on setting time and temperature of cement paste

This paper present the study of the effect of adding different sugar types such as (Granular, Caster, Brown and Beet) on setting time and temperatures of hydration of cement paste. The effect of sugar on the setting times was checked by testing numbers of cement paste samples, that produce from 35% w/c ratio and different sugar type and ratio (0.5%, 1.5%, 2.5% and 5%) by the cement weight using Vi-cat needle apparatus. While the temperatures of hydration heat were measured by using Thermocouples, and changes in the heat of hydration were clearly recognised. The results of the experimental works show that: adding any type of cane sugar (Granulated, Caster and Brown sugar) in proportion (0.5% and 1.5%) the sugar was works as a concrete retardant, but these type of sugar worked as concrete accelerator when used in proportion (2.5% and 5%). However; adding Beet sugar in proportion (0.5%, 1.5%, 2.5% and 5%) was working as a concrete retardant. On the other hand, the hydration temperatures increased by adding sugar and the high peak they reached was about 33.890C at 0.30 water ratio with 1.5% sugar content. It obvious, for all sugar type (1.5% by cement weight) was the optimum sugar proportion to retard the final setting time of the cement pastes of different w/c ratios, but the higher sugar contents cause a decrease in the final setting time. On other hand, the initial setting time was decreased and accelerated when sugar was added to the paste. As well as adding sugar to the cement paste improved it physically by reduced the cracking and the bleeding on the surface of the sample. © IAEME Publication

The Impact of Rice Husks Ash on Some Mechanical Features of Reactive Powder Concrete with High Sulfate Content in Fine Aggregate

The sulfate issue in fine aggregate grows with time and it is not easy to gain a fine aggregate with sulfates amount within the specifications of Iraqi standard. Internal sulfate attack is regarded as a significant problem in concrete construction in Iraq and the Middle East countries. One of the modern generations in ultra-high performance concrete is Reactive powder Concrete (RPC) that has been prepared for cemented materials using microstructure improvement methods. RPC has gained attention from both academia and engineering fields with extensive applications. This study presents an experimental research on the impact of Rice Husks Ash (RHA) as replacement percentage of cement upon some mechanical features of RPC with high sulfate content in fine aggregate (Three percentages of SO3 = 0.16, 0.5 and 1.2%). Three percentages of RHA (0, 10 and 15%) as a partial substitution of cement weight have been used in this research. The compressive and the flexural strengths have been adopted to attain the impact of adding RHA. The outcomes have showed that the incorporation of RHA has an important influence on the compressive-strength for both with and without internally sulfate attacking. The result has indicated that using 10% of RHA as a partial cement substitution has increased the effectiveness of RPC by its mechanical features (compressive and flexural-strengths) without internal sulfate attacked

Applying of No-fines concretes as a porous concrete in different construction application

Recently, the demands on the concretes with no fines aggregate has been increased as a results of the industry revolution. Many researchers are trying to recycle the concretes and rubble. In addition, the increase in noise in the surrounding environment as a result of the growing population and cars has generated an urgent need to produce concretes characterized by good sound insulation. No-fines concretes is considered as a kind of porous lightweight concretes, gained by removing the sand from the ordinary concrete mixture. The aim of this study is replacing the coarse aggregate by waste ceramics in order to reduce the wastes as well as investigate strengths against compression s, density and porosity of No-fines concretes before and after substitution the coarse aggregate by waste ceramics. The methodology of this research paper has been mainly depending on strengths against compression s test and the measured ultrasonic pulse velocity as well as the density. The investigational research has been implemented by 54 samples cast by six various blending proportion consisting of (cement, coarse aggregate, water) utilizing ceramic wastes (CWs) as a substation ratio of coarse aggregates in making concretes free of fine aggregate, so that the proportions of ceramic residues are (0, 10%, 20, 30, 40, 50) as a partial substation of the coarse aggregates and examined at the ages of (7, 28 and 90) days. The mechanism of failure has been detected and categorized beside the concrete's density and void percentage have been collected. The results show that, the increasing the substitution ratio for waste ceramic within the no-fine mixtures cause a decrease in the density with increasing the strengths against compression s for the specimens

The impact of grinding time on properties of cement mortar incorporated high volume waste paper sludge ash

Cement is considered a base material in preparing blending mixtures that applying in various projects in the civil engineering field. Nevertheless, the cement production process cause indubitable negative environmental influences such as emitting CO2. The production of cement produces around 7% of the global CO2 emissions. Thus, searching for alternate binders in building processes to minimise or substitute cement has been one of the social problems. A by-product or waste products are among the potential alternatives to the mentioned problem. The present investigation involves the consumption of paper sludge ash (PSA) waste as cement replacement to produce environmentally friendly, cementitious material. Limited studies were addressed the PSA grinding time impact on mortar or concrete properties. Moreover, limited studies replaced the cement with high volume of PSA. Therefore, during this study, the effect of grinding time and replacement level (up to 50%) of the PSA on the surface electrical resistivity and compressive strength of mortar were investigated. Three grinding periods (in addition to without grinding), two replacement levels and three testing ages were considered. The results indicated that grinding the PSA for 10 minutes and use it to replace up to 50% of the cement content have similar mechanical and durability performance to ordinary Portland cement after 28 curing days. This innovative binder will also cause a major difference in decreasing the building materials cost and CO2 emissions

Impact of Substitute Portland Cement with CKD on the Mechanical and Durability Characteristics of Cement Mortar

Cement mortar is a binding material that is made of cement, sand and water. In general, mixes of mortar are made of raw materials. However, using raw materials in producing mortar leads to many environmental and economic issues. One of the most common solutions to reduce these issues is replacing raw materials by waste and/or by-product materials; especially replacing cement. The aim of this research is to explore the characteristics of mortar mixes after partially replacing Ordinary Portland Cement (OPC) by Cement Kiln Dust (CKD) at three percentages (10%, 20% and 30%) in terms of initial and final setting time, compressive strength and Ultrasonic Pulse Velocity (UPV). The control mortar specimen (mortar containing OPC only) results were adopted for comparison with results of mortar mixes that incorporated CKD. Results showed that increment in CKD replacement percentages led to a decrement in the compressive strength and UPV and an increment in the setting time

Studying the effect of shear stud distribution on the behavior of steel-reactive powder concrete composite beams using ABAQUS software

Using the ABAQUS software, this article presents a numerical investigation on the effects of various stud distributions on the behavior of composite beams. A total of 24 continuous 2-span composite beam samples with a span length of 1 m were examined (concrete slab at the top and steel I-section at the bottom). The concrete slab used is made of a reactive powder concrete with a compressive strength of 100.29 MPa. The total depth of each sample was 0.220 m. The samples were separated into four groups. The first group involved 6 specimens with shear connectors distributed into 2 rows with different distances (65, 85, 105, 150, 200, and 250 mm). The second group had the same spacing of shear connectors as the first group except that the shear connectors were distributed with one row along the longitudinal axis. The third group consisted of six specimens with single and double shear connectors distributed along the longitudinal axis. The fourth group included six specimens with one row of shear connectors arranged in a staggered distribution along the longitudinal axis. Results show that the optimum spacing was 105 mm in all groups and the deflection in group four fluctuated up and down due to the non-symmetrical distribution of the shear connectors

Stabilization of Soft Soil by a Sustainable Binder Comprises Ground Granulated Blast Slag (GGBS) and Cement Kiln Dust (CKD)

Due to its significant deficiencies such as low permeability, low bearing and shear strength, and excessive compressibility, soft soil is one of the most problematic types of soil in civil engineering and soil stabilization can be considered a suitable technique for pavements. This study investigates the use of ground granulated blast slag (GGBS) and cement kiln dust (CKD) as stabilizers for soft soil. Thus, this study involves two optimization stages; in the first stage, GGBS was incorporated into 0%, 3%, 6%, 9%, and 12% by the weight of cement to obtain the optimal percentage, which was 6%. Then, the optimal GGBS was blended with CKD in a binary system at 0%, 25%, 50%, 75%, and 100% by the dry weight of the soil. The testing program used in this paper was Atterberg limits with compaction parameters to investigate the physical properties and unconfined compressive strength (USC) at 7 and 28 days to examine the mechanical characteristics. In addition, the microstructures of the soil specimens were tested at 7 and 28 days using scanning electron microscopy (SEM). The findings reveal that the binary system enhanced the physical and mechanical properties of the soft soil. The optimum binder achieved in this study was 6% (25% GGBS and 75% CKD), which generates an increase in strength of about 3.3 times in 7 days, and of 5.5 times in 28 days in comparison to the untreated soil. The enhancement was attributed to the formation of the hydration products as approved by SEM. Consequently, in the case of soft subgrade soils, this technique can increase the pavement’s bearing capacity and performance

Production of Ternary Blend Binder as an Alternative to Portland Cement

Environmental pollution and the relatively high cost of waste disposal have been a major focus for scientists around the world, leading researchers to find a solution to reuse waste materials in different applications. Additionally, landfills are considered one of the biggest crisis facing the Iraqi government. Therefore, this study aims to present a new ternary mixture that consists of OPC in addition to Pulverized Fuel Ash (PFA), Ground Granulated Blast Furnace Slag (GGBS) by utilizing it as a partial substitution of cement. A new ternary mortar mixtures containing four substitution levels of cement with GGBS and PFA (0%, 30 %, 50% and 70% by weight) were carried out. The Ultrasonic Pulse Velocity (UPV) and compressive strength tests were adopted to show the influence of GGBS and PFA on mechanical features of cement mortar. Findings indicated that, the compressive strength values were reduced with increasing the GGBS and PFA proportions at all curing ages. For 70% replacement, the compressive strength values were the lowest values comparison with that for control specimens. In contrast, the GGBS and PFA had a negative and positive impacts on the UPV of mortar depending on the substitution ratio. At 30 % substitution levels, the velocity value was enhanced, while other substitution ratios affected negatively on the UPV values

Impact of high volume GGBS replacement and steel bar length on flexural behaviour of reinforced concrete beams

The Ordinary Portland Cement (OPC) is one of the major ingredient utilized for the manufacture of concrete. The manufacturing of cement includes the release of huge amounts of CO2 gas as a main contributor for greenhouse influence and global warming. Several researchers have investigated the characteristics of OPC concrete utilizing cementitious materials like fly ash, silica fume, and Ground Granulated Blast furnace Slag (GGBS) as replacement materials. The article aims to investigate experimentally the flexural behavior of concrete beams with GGBS. The experimental work was divided into three stages, the first one consists of six reinforced concrete beam specimens with (0%, 40% and 60%) of GGBS. During this stage, the used steel bars were 8 mm diameter and 500 mm in length. In the second stage, the length of the steel bars was reduced to 400 mm with the best mixture of (GGBS+OPC) that obtained from stage 1. In the third stage, the best length of steel bars was used with the best (GGBS+OPC) ratio to be tested at 7, 14 and 28 days from the date of casting. Consequences of this exploration suggests that replacement of OPC with 40 percent GGBS with 500 mm steel bar length can be used in reinforced concrete specimens as it shows comparable results relative to control mixtures (0% GGBS)

The Impact of Using Different Ratios of Latex Rubber on the Characteristics of Mortars Made with GGBS and Portland Cement

Preserving natural resources and implementing the concepts of sustainable engineering to approach the zero waste concept helped in reducing the detrimental environmental effects in the last two-decade. Proposed re-using of Ground Granulated Blast Furnace Slag (GGBS) as an alternate solution is to get rid of them and profit from them concurrently. In this process, GGBS is used as cement substitute material to enhance mortar characteristics. On the other hand, the required water for concrete mixture should be characterized by several characters, which similar to drinkable water, therefore, using of Latex Rubber as a water substitution reduces the demand for such water in the construction industry. In this project, percentages of GGBS that have been used were 0%, 10%, 30%, and 50% which compatible with (0, 10, 20 and 30) % of Latex Rubber. Suitable tests were performed to measure properties of mortar by GGBS and Latex Rubber such as setting time, compressive strength and Permeability test (Electrical resistivity). The results obtained indicate that the setting time reduced with increasing Rubber Latex in spite of increasing the proportion of water to binder. Additionally, increasing the Latex Rubber amount leads to decrease the compressive strength and electrical resistivity of mortars