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"Banyak penelitian yang telah menggunaka serat baja dalam campuran beton normal dan telah dilakukan dalam beberapa negara bagian di dunia. Namun, dikarenakan harga serat kawat baja itu sangat mahal di Indonesia, maka penggunaan serat kawat bendrat untuk menggantikan serat baja itu dan menggunakannya dalam campuran beton yang diteliti dalam penelitian ini. Serat kawat bendrat ini berdiameter 0,8mm dipotong dengan panjang 30 mm dan digunakan dalam campuran beton sebagai tulangan mikro beton yang diprediksi mampu meningkatkan kuat tekan beton dan mengurangi susut beton. Jumlah serat ini digunakan dari berat semen PCC dengan variasi 0%, 4%, 6%, 8%, 10% dan 12% dengan target kuat tekan fc? 25MPa. Untuk uji kuat tekan beton, benda uji akan dibuat dalam silinder kecil yang berdiameter 100mm dan tinggi 200 mm yang dites pada hari ke 3,7,14, dan 28 hari serta silinder besar dengan diameter 150 mm dan tinggi 300 mm yang akan di tes 28 hari agar diperoleh faktor konversi silinder kecil ke besar. Sedangkan untuk pengujian susut beton di uji pada balok berukuran 100mm x 100mm x 500mm (Standar UNI 6555) dan balok 75mm x 75mm x 254mm (Standar ASTM C49004) yang diuji selama 28 hari. Hasil penelitian menunjukkan bahwa penggunaan serat kawat bendrat dalam campuran beton meningkatkan kuat tekan beton sebesar 5,682% pada komposisi 6% serat kawat bendrat dan mengurangi susut sebesar 7,93% pada komposisi 10% serat kawat bendrat dan juga penggunaan serat kawat bendrat menurunkan kelecakan nilai slump beton.

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Many experiments on the use of steel fiber to strengthen the quality of normal concrete have been done in some regions of the world. As the price of this fiber in Indonesia is considerably expensive, the use of annealed wire is proposed to be a replacement of it and used as additives for concrete mixture is investigated in this research. This annealed wire of 0,8mm diameter is cut into pieces size of 30 mm length named as annealed-wire fiber (AW fiber) and added into normal concrete mixture as reinforcing fiber to increase the concrete compressive strength and reduce the shrinkage of concrete. The amount of this fiber measured in weight proportion to the content of Portland Composite Cement (PCC) is designed as 0%, 4%, 6%, 8%, 10%, and 12% based on the moderate concrete compressive strength fc? 25MPa. The concrete compressive strength is evaluated to numbers of cylinder type specimens size of 100 mm diameter by 200 mm height tested on 3 days, 7 days and 14 days and of 150 mm diameter by 300 mm height tested on 28 days of concrete age. And the shrinkage test is evaluated to numbers of beam type specimens size 100mm x 100mm x 500mm (UNI 6555 Standard) and 75mm x 75mm x 254mm (ASTM C490-04) The result from this experiment shows that the addition of AW fiber is increased the concrete compressive strength until 5,682% at 6% annealed-wire fiber composition and reduce 7,93% shrinkage at 10% annealed-wire fiber composition but decrease the workability by reducing the slump value."

"internal curing is promoted as a way tpo mitigate autogenous shrinkage in high-performance concrete having a low water binder ratio (w/b). Different methods of internal curing have been proposed. In this study, the effect of substituting 20% of normalweight sand by an equal mass of lightweight sand on the development of shrinkage was investigated on a 0.35 w/b high performance concrete . Shrinkage was monitored using vibrating wire gauges cast at the center of 100x100x400 mm (4x4x16 in.) concrete samples. Two samples were sealed with self-adhesive aluminum foil to present a closed curing system without any exchanged of humidity between the concrete and its environment, After demolding at the age if 23 to 25 hours. two other samples were cured under water for 6 days . Thereafter these two samples were removed from water and maintained at 23 C (73 F ) and a 50% relative humidity (RH) Environment . Experimental results clearly demonstrate the effeciency of a 20% substitution of normalweight by a lightweight sand to reduce autogenous and drying shrinkage . The Incorporation of 20% lightweight sand did not significantly affect the 28-day compressive strength. The cementitious matrix presented low chloride ion permeability. Internal curing through the use of partial replacement of normalweight sang by lightweight sand definitely represent and efficient method to diminish autogenous and drying shrinkage in low w/b concretes where external water curing does not allow in-depth curing of concrete"

"Self-Consolidating Concrete (SCC) mixtures for use in Prestressed Concrete applications are evaluated in this paper . Twenty one SCC mixtures were made under laboratory conditions with varying water to cementitious materials ratios, sand to total aggregate rations, and cementitious materials combinations (type III cement , class C fly ash, ground-granular blast-furnance slag, and silica fume). The SCC mixtures archived prestress transfer compressive strengths between 5470 and 9530 psi (38 and 66 MPa). The moduli of elasticity of the SCC Mixtures were in reasonable agreement with the elastic stiffness assumed during the design of conventional slump concrete structures. The long term drying shrinkage strain for all the SCC mixtures were approximately the same or less than those measured for the control mixtures. A change in sand to total aggregate ratio had no significant effect on the long term drying shrinkage. At later ages of 56 and 112 days, the measured drying shrinkage corresponded reasonable well to those predicated by the ACI 209 procedure."