Binary Cementitious Blends Research Articles

Micro and Nano Engineered High Volume Ultrafine Fly Ash Cement Composite with and without Additives

This paper presents the effect of silica fume and nano silica, used individually and in combination with the set accelerator and/or hydrated lime, on the properties of class F high volume ultra fine fly ash (HV-UFFA) cement composites, replacing 80 % of cement (OPC). Compressive strength test along with thermogravimetric analysis, X-ray diffraction and scanning electron microscopy were undertaken to study the effect of various elements on the physico-chemical behaviour of the blended composites. The results show that silica fume when used in combination with the set accelerator and hydrated lime in HV-UFFA cement mortar, improves its 7 and 28 day strength by 273 and 413 %, respectively, compared to the binary blended cement fly ash mortar. On the contrary, when nano silica is used in combination with set accelerator and hydrated lime in HV-UFFA cement mortar, the disjoining pressure in conjunction with the self-desiccation effect induces high early age micro cracking, resulting in hindering the development of compressive strength. However, when nano silica is used without the additives, it improves the 7 and 28 day strengths of HV-UFFA cement mortar by 918 and 567 %, respectively and the compressive strengths are comparable to that of OPC.

Effect of Quarry Waste on Self-Compacting Concrete Containing Binary Cementitious Blends of Fly Ash and Cement

This paper presents the results of the experimental work conducted to study the effect of quarry waste on self-compacting concrete containing binary cementitious blends of fly ash and cement. For this purpose nine trial mixes were prepared, where the percentage replacement of river sand by quarry waste was 0%, 10%, 20%, 30%, 40%, 50%, 70%, and 100% to study the flowability characteristics of SCC. In all, 108 cube samples and 54 cylindrical samples were cast to study the strength parameters of SCC with and without quarry waste. The water to binder ratio was maintained at 0.36% while the dose of chemical admixture was 2.2% by weight of cement. For all trial mixes the fly ash percentage replacement to cement was kept constant at 30%. Based on the standard flowability test a visual stability index has been provided to all the trial mixes. Quarry waste replacement showed the desirable results that can suggest the usage in self-compacting concrete as well as in normally vibrated concrete.

Rheology of ordinary and low-impact environmental concretes

This study deals with the rheological properties of concrete mixtures incorporating various types of mineral additions as a partial replacement of cement in order to produce a low-impact environmental concrete. The control mixture contained only Portland cement as the binder, while the remaining mixtures incorporated binary cementitious blends of slag, limestone filler, and fly ash with different rates of replacement. After mixing, the plastic viscosity and yield stress of the concretes were evaluated at different slump values using a rheometer apparatus. The results showed that the type of mineral additions and the rate of substitution affect the rheological parameters of low-impact environmental concrete. Indeed, increasing the degree of substitution leads to an increase in the plastic viscosity of the concrete made with different types of additions used in this study.

Hydration Kinetics and Strength Development of Waste Paper Sludge Ash (WPSA) with Different Particle Size as Binary Blended Cement

In this study, four types of Waste Paper Sludge Ash (WPSA) were explored for use as Supplementary Cementitious Materials (SCM) in binary system. The WPSA use varies in particle size range and surface area however similar in chemical composition. At first stage, Ordinary Portland Cement (OPC) was replaced by WPSA at 5% mass to mass basis as blended cement. Four size of WPSA was prepared which are unsieve, retained at 63μm, retained at 45μm and pan. WPSA blended cement (WPSABC) was introduced from the four size of WPSA that prepared earlier. Water to cement ratio selected was 0.50 and it keep constant at all type of blended cement. When compared with the control mix, result shows that hydration kinetics is affected by the particle size of WPSA. Pan WPSA has slightly higher peak of hydration kinetics and compressive strength of blended cement. At second stage, Pan WPSA was selected to undergo the further investigation on its performance. Pan WPSABC were prepared at replacement level of 5%, 10%, 15% and 20%, mass to mass basis. Same method and w/c ratio was used and compared with control mix. From the result, it is found that the peak for rate of heat evolution of Pan WPSABC occur earlier and slightly lower as compared to OPC. Pan WPSA also achieved it optimum strength at 5% replacement level which is more than control mix.

Effect of grinding method and particle size distribution on early-age properties of blended cements

This paper describes the influence of the producing method (inter-grinding and separate grinding) and particle size distribution (PSD) on early-age properties of binary and ternary blended cements. Various experiments were carried out to determine properties of cement paste including normal consistency, time of setting, heat of hydration and calcium hydroxide content. In addition, compressive and flexural strength tests were carried out on cement mortars. The results show that for achieving the same percentage of 45 μm residue in blended cements containing Trass, inter-grinding was less energy demanding than separate grinding (shorter grinding time was required). Moreover, PSD and early-age properties of blended cements with the same percentage of 45 μm residue were not significantly affected by the grinding method. Additionally, the hydration reactions of blended cements were slightly accelerated by the increase of fineness value. Furthermore, the use of cements with high fineness is not economically beneficial owing to its low effect on early-age properties.

전기로 환원슬래그를 혼합하여 제작한 2성분계 시멘트의 수화반응 해석 및 콘크리트 적용 성능 평가

전기로 환원슬래그를 혼합하여 제작한 2성분계 시멘트의 수화반응 해석 및 콘크리트 적용 성능 평가

Durability performance and engineering properties of shale and volcanic ashes concretes

Designing a sustainable concrete has become a vital requirement for today’s concrete. Introducing various cementing and pozzolanic materials in concrete in replacement of Portland cement seems to be the appropriate way to lower the environmental impact of concrete industry.This paper reports results on concrete performance produced with two types of pozzolanas including natural pozzolana (NP) obtained from volcanic ash and shale ash (SA) used, in various proportions ranged from 10–45%, as a partial substitute of Portland cement (PC). Concrete mixtures were designed with a wide range of water-to-cementitious ratios (w/c) ranged from 0.79 to 0.45. The key mechanical properties and durability performance of binary blended cement concretes were investigated.Using both NP and SA has resulted in a strength loss; while SA seems to perform better than NP in terms of strength development and durability performance. The blended cement concretes with 10–15% pozzolanas was found to have a good resistance to carbonation and chloride ions ingress and are freeze–thaw durable. However, with replacement level higher than 20%, the durability factor, chloride ions and carbonation resistance drop down.Overall, the results indicate that the mechanical and durability performances of binary blended cements with NP and SA are strongly linked to their intrinsic characteristics including chemical composition, fineness, particle size distribution and potential reactivity.

Mass Change Prediction Model of Concrete Subjected to Sulfate Attack

The present study suggested a mass change prediction model for sulfate attack of concrete containing mineral admixtures through an immersion test in sulfate solutions. For this, 100% OPC as well as binary and ternary blended cement concrete specimens were manufactured by changing the types and amount of mineral admixture. The concrete specimens were immersed in fresh water, 10% sodium sulfate solution, and 10% magnesium sulfate solution, respectively, and mass change of the specimens was measured at 28, 56, 91, 182, and 365 days. The experimental results indicated that resistance of concrete containing mineral admixture against sodium sulfate attack was far greater than that of 100% OPC concrete. However, in terms of resistance against magnesium sulfate attack, concrete containing mineral admixture was lower than 100% OPC concrete due to the formation of magnesium silicate hydrate (M-S-H), the noncementitious material. Ultimately, based on the experimental results, a mass change prediction model was suggested and it was found that the prediction values using the model corresponded relatively well with the experimental results.

Compressive strength and chloride resistance of self-compacting concrete containing high level fly ash and silica fume

The influence of high-calcium fly ash and silica fume as a binary and ternary blended cement on compressive strength and chloride resistance of self-compacting concrete (SCC) were investigated in this study. High-calcium fly ash (40–70%) and silica fume (0–10%) were used to replace part of cement at 50, 60 and 70wt.%. Compressive strength, density, volume of permeable pore space (voids) and water absorption of SCC were investigated. The total charge passed in coulombs was assessed in order to determine chloride resistance of SCC. The results show that binary blended cement with high level fly ash generally reduced the compressive strength of SCC at all test ages (3, 7, 28 and 90days). However, ternary blended cement with fly ash and silica fume gained higher compressive strength after 7days when compared to binary blended fly ash cement at the same replacement level. The compressive strength more than 60MPa (high strength concrete) can be obtained when using high-calcium fly ash and silica fume as ternary blended cement. Fly ash decreased the charge passed of SCC and tends to decrease with increasing fly ash content, although the volume of permeable pore space (voids) and water absorption of SCC were increased. In addition when compared to binary blended cement at the same replacement level, the charge passed of SCC that containing ternary blended cement was lower than binary blended cement with fly ash only. This indicated that fly ash and silica fume can improve chloride resistance of SCC at high volume content of Portland cement replacement.

Effect of ultrafine fly ash on mechanical properties of high volume fly ash mortar

This paper presents the effect ultrafine fly ash (UFFA) on compressive strength development of mortars containing high volume class F fly ash as partial replacement of cement. The experimental works are divided into two parts. Part one is conducted in binary blended cement mortar where Portland cement (PC) type I is replaced by UFFA at level of 5%, 8%, 10%, 12% and 15% (by wt). In this part, cement mortar and high volume fly ash (HVFA) mortars containing 40%, 50%, 60% and 70% of class F fly ash are also prepared and used as control mortars. The UFFA level which exhibited highest compressive strength is then selected and used in part two where the effect of UFFA in high volume fly ash replacement is evaluated. The study reveals that the cement mortars with 8% UFFA of cement replacement exhibited higher compressive strength at 7 and 28days than control mortars. There is also a great improvement on compressive strength of HVFA mortars, particularly at early age. The large surface area of the UFFA promotes the hydration process and enhances the microstructure of the cement mortars to yields better strength and mechanical properties. In this study, the microstructure and phase identification after 28days are also presented based on backscattered electron (BSE) image and x-ray diffraction (XRD) analysis of paste samples. The results indicate the effectiveness of UFFA in producing high packing density and in accelerating the pozzolanic activity to produce more C-S-H gel by consuming calcium hydroxide (CH) in order to improve the mechanical properties of HVFA mortars.

Effect of Relative Levels of Mineral Admixtures on Strength of Concrete with Ternary Cement Blend

In the present scenario to fulfill the demands of sustainable construction, concrete made with multi-blended cement system of OPC and different mineral admixtures, is the judicious choice for the construction industry. Silica fume (SF) and fly ash (FA) are the most commonly used mineral admixtures in ternary blend cement systems. Synergy between the contributions of both on the mechanical properties of the concrete is an important factor. This study reports the effect of replacement of OPC by fly ash (20, 30, 40 and 50 % replacement of OPC) and/or silica fume (7 and 10 %) on the mechanical properties of concrete like compressive strength and split tensile strength, with three different w/b ratio of 0.3, 0.4 and 0.45. The results indicate that, as the total replacement level of OPC in concrete using ternary blend of OPC + FA + SF increases, the strength with respect to control mix increases up to certain replacement level and thereafter decreases. If the cement content of control mixes at each w/b ratio is kept constant, then as w/b ratio decreases, higher percentage of OPC can be replaced with FA + SF to get 28 days strength comparable to the control mix. A new method was proposed to find the efficiency factor of SF and FA individually in ternary blend cement system, based on principle of modified Bolomey’s equation for predicting compressive strength of concrete using binary blend cement system. Efficiency factor for SF and FA were always higher in ternary blend cement system than their respective binary blend cement system. Split tensile strength of concrete using binary and ternary cement system were higher than OPC for a given compressive strength level.

Suitability of Nigerian Agricultural By-Products as Cement Replacement for Concrete Making

This work investigated the strength characteristics of binary blended cement concrete made with Ordinary Portland Cement (OPC) and each of eight agricultural by-products in South Eastern Nigeria, namely Rice Husk Ash (RHA), Saw Dust Ash (SDA), Oil Palm Bunch Ash (OPBA), Cassava Waste Ash (CWA), Coconut Husk Ash (CHA), Corn Cob Ash (CCA), Plantain Leaf Ash (PLA), and Paw-Paw Leaf Ash (PPLA). 105 concrete cubes of 150mm x 150mm x 150mm were produced at percentage OPC replacement with each of the eight ashes of 5%, 10%, 15%, 20%, and 25%. Three concrete cubes for each percentage replacement of OPC with each ash and the control were tested for saturated surface dry bulk density and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. The compressive strengths of binary blended cement concrete increased with curing age and decreased with increase in percentage replacement of OPC with pozzolans. The 3-14 day compressive strength values were much lower than the control values for all percentage replacements of OPC with pozzolan. However, the 90-day strength at 5-10% replacement of OPC in binary blending with each of the eight pozzolans was higher than that of the control, ranging from 24.50N/mm 2 for 10% replacement of OPC with coconut husk ash (CHA) to 30.2N/mm 2 for 5% replacement of OPC with RHA compared with the control value of 23.8N/mm 2 . Thus, all the eight agricultural by-products investigated in this work could be good for binary blending with OPC in making structural concrete. However, since blended cement concrete take a longer time to attain adequate strength than 100% OPC concrete, major structural elements constructed with blended cement concrete should be allowed a longer time before loading, say 28-50 days for 5-15% replacement of OPC with agricultural by-product pozzolans and 50-90 days for 15-25% replacement of OPC.

Application of non-corrosive barchip fibres for high strength concrete enhancements in aggressive environments

The trouble of sea water attacks in marine structures has suffered the engineers for decades. Until present, the most popular approach used to minimize the detrimental effects resulted by the sea water is the applications of high strength high performance concrete. The binary or ternary blended cement system is applied to improve the impermeability properties of the resulting concrete. Nonetheless, the sulphate attacks and the expansions and shrinkages caused by the environments would induce cracks at the structures. Once the cracks are initiated, it allows the penetration of harmful substances and ultimately reduces the durability of the structure in a substantial manner. In this experiment, a mechanical approach is employed to improvise the concrete in the aspects of strength and durability properties. The barchip fibre that is non-corrosive, short and discrete is introduced into high strength concrete so as to provide localize reinforcing effects to restrain the cracks development in the matrix. The specimens were exposed to three types of aggressive environments; namely tropical climate (A-series), alternate air and sea water in a 14-day cycle (4days in sea water+10days in air) (N-series) and continuous immersion in the sea water (W-series). Parameters like the compressive strength, permeability, porosity, chloride penetration were examined. The mineralogical and microstructures were studied by the means of X-ray diffraction (XRD) and scanning electron microscope (SEM) examination, respectively. The findings in these studies solidify the justifications provided in the discussions. The results verify that 1.8% would be the optimum dosage of barchip fibre that could provide greatest enhancements to the concrete. When the exposure period is prolonged, the increments in the compressive strength were above 12% and the permeability was also reduced. Together with other improvements, it could be concluded that the incorporation of barchip fibre has successfully suppressed the damaging effects that arise from the aggressive environments.

해양환경을 고려한 다성분계 시멘트 콘크리트의 황산염 및 동결융해 저항 특성

Recently, concrete using multicomponent blended cement has been required to increase the freeze-thaw and sulfate resistances of concrete structures exposed to a marine environment. Thus, the purpose of this study was to propose the use of concrete containing multicomponent blended cement as one of the alternatives for concrete structures exposed to a marine environment. For this purpose, batches of concrete containing ordinary portland cement (OPC), binary blended cement (OPC-G, G: ground granulated blast slag), ternary blended cement (OPC-GF, F: fly ash), and quaternary blended cement (OPC-GFM, M: mata-kaolin) were made using a water-binder ratio of 50%. Then, the durability levels, including thesulfate and freeze-thaw resistances, were estimated for concrete samples containing OPC, OPC-G, OPC-GF, and OPC-GFM. It was observed from the tests that the durability levels of the concrete samples containing OPC-G and OPC-GF were found to be much better than that of the concrete containing OPC. The optimum mixing proportions were a40% replacement ratio of ground granulated blast slag for the binary blended cement and a30% replacement ratio of ground granulated blast slag and 10% fly ash for the ternary blended cement.

Compressive Strength of Binary and Ternary Blended Cement Mortars Containing Fly Ash and Silica Fume under Autoclaved Curing

Cement industry is a one of the major sources of environmental pollution therefore the reduction of cement demand should be improved. Fly ash and silica fume is a by-product of industries and it should be reused to reduce the waste pollution. Thus, this study investigated the use of fly ash and silica fume as a cement replacement in binary and ternary blended cements on compressive strength and physical properties of mortar. Autoclaved curing at 130 °C and 20 psi of pressure for 9 h was used in this study. The results show that the compressive strength of binary blended cement mortar with FA tends to decrease with increased FA replacement and shows compressive strength lower than PC control. However, compressive strength of binary blended cement mortar with SF was improved and shows compressive strength higher than that of PC control. The compressive strength of ternary blended cement mortar was higher than binary blended cement at the same level replacement and it increases with increased SF replacement. Moreover, ternary blended cement mortar containing 10%SF by weight contribute in giving compressive strength higher than PC control. The incorporation of FA with SF can enhance workability of blended cement mortar containing only SF replacement.

콘크리트의 황산 및 황산염 침투 저항성에 미치는 광물질 혼화재의 영향

하수도, 오·폐수, 토양 속, 지하수 및 해수 등의 환경에 건설되는 콘크리트 구조물은 산 및 황산염에 노출되어 있다. 이 같은 산 및 황산염 침투로 포틀랜드 시멘트 중의 수화생성물과 산 및 황산염 이온이 반응하여 팽창 수화물을 생성함으로써 콘크리트에 팽창 및 균열을 발생시켜, 결국 콘크리트 매트릭스에 손상을 일으킨다. 따라서 이 연구의 목적은 콘크리트의 황산 및 황산염 침투 저항성에 미치는 광물질 혼화재의 영향을 평가하여, 황산 및 황산염 침투에 대한 고저항성 콘크리트를 제시하는 것이다. 이를 위하여 광물질 혼화재의 형태 및 비율을 변화시킨 OPC, 2성분계 및 3성분계의 3가지 종류의 시멘트를 사용하여 물-결합재비 32% 및 43%인 콘크리트를 제조하였다. 제작된 콘크리트시편은 민물, 5% 황산, 10% 황산나트륨 및 10% 황산마그네슘 용액에 재령 28, 56, 91, 182 및 365일 동안 각각 침지시켰다. 콘크리트의 황산 및 황산염 침투 저항성을 평가하기 위하여 외관변화 관찰과 압축강도 비 및 질량 변화율을 측정하였다. 그 결과, 광물질 혼화재를 혼입한 콘크리트의 황산 및 황산나트륨 침투에 대한 저항성은 OPC 콘크리트 경우보다 훨씬 우수한 것으로 나타났으나, 황산마그네슘의 경우 비결합재질의 규산마그네슘수화물(M-S-H)의 형성으로 광물질 혼화재를 혼입한 콘크리트가 OPC 콘크리트보다 불리한 것으로 나타났다.

Chloride penetration in binary and ternary blended cement concretes as measured by two different rapid methods

In this study, the two rapid chloride permeability tests; the AASHTO’s rapid chloride permeability test (RCPT) and the University of Cape Town (UCT) chloride conduction test were employed and compared using concrete specimens cast with effective w/b ratio of 0.48 and applying seven days of curing. Fly ash and blast furnace slag were used in a systematic replacement of cement at the levels of 25%, 50%, and 70%. In addition, silica fume was added at 10% cement replacement. The matrix therefore, was either a binary or ternary blend of cementitious materials. The experimental results were tested for significance using standard statistical methods. The results indicate that ternary blends of 25% fly ash and 10% silica fume exhibited significant decrease in charge passed compared to 25% fly ash. Similarly, the charge passed in the ternary blends of 25% BFS and 50% BFS with addition of 10% silica fume showed lower charge compared to their respective binary blends. The UCT test has been faster and more convenient to use than the RCPT. However, when binary and ternary blends were compared, the RCPT proved to be more sensitive in showing appreciable differences in the values obtained while such differences were insignificant when the UCT test was used.

Ternary blend cements concrete. Part II: Transport mechanism

With today’s extensive use of cements containing two or more additions (blended cements), predicting concrete durability on the grounds of its strength alone leads to errors that may affect the service life of the resulting structures. Indeed, concrete of a given strength class can be made from different materials and proportions of widely varying durability. The present study evaluated water absorption, sorptivity and initial surface absorption in concrete made with unadditioned Portland, binary (limestone) and ternary (limestone and granulated slag) blend cement.

Utilization of municipal solid waste incineration (MSWI) fly ash in blended cement: Part 1: Processing and characterization of MSWI fly ash

This paper is the first of a series of two articles dealing with the processes applied to MSWI fly ash with a view to reusing it safely in cement-based materials. Part 1 presents two stabilization processes and Part 2 deals with the use of the two treated fly ashes (TFA) in mortars. Two types of binder were used: an Ordinary Portland Cement (OPC) containing more than 95% clinker (CEM I 52.5R) and a binary blend cement composed of 70% ground granulated blast furnace slag and 30% clinker (CEM III-B 42.5N). In this first part, two stabilization processes are presented: the conventional process, called “A”, based on the washing, phosphation and calcination of the ash, and a modified process, called “B”, intended to eliminate metallic aluminum and sulfate contained in the ash. The physical, chemical and mineralogical characteristics of the two TFA were comparable. The main differences observed were those expected, i.e. TFA-B was free of metallic aluminum and sulfate. The mineralogical characterization of the two TFAs highlighted the presence of large amounts of a calcium aluminosilicate phase taking two forms, a crystalline form (gehlenite) and an amorphous form. Hydration studies on pastes containing mixed TFA and calcium hydroxide showed that this phase reacted with calcium hydroxide to form calcium aluminate hydrates. This formation of hydrates was accompanied by a hardening of the pastes. These results are very encouraging for the reuse of such TFA in cement-based materials because they can be considered as pozzolanic additions and could advantageously replace a part of the cement in cement-based materials. Finally, leaching tests were carried out to evaluate the environmental impact of the two TFAs. The elements which were less efficiently stabilized by process A were zinc, cadmium and antimony but, when the results of the leaching tests were compared with the thresholds of the European landfill directive, TFA-A could nevertheless be accepted at landfills for non-hazardous waste. The modifications of the process led to a significant reduction in the stabilization of chromium, selenium and antimony.